diff --git a/R/15.Lattice_paths/servindc.R b/R/15.Lattice_paths/servindc.R
new file mode 100644
index 0000000..31eaee5
--- /dev/null
+++ b/R/15.Lattice_paths/servindc.R
@@ -0,0 +1,10 @@
+#  Solution to Euler problem 15
+Lattice_paths <- function(n){
+  n <- as.integer(n)
+  p <- 0
+  for (i in 0:n){
+    p <- p + (factorial(n)/(factorial(n-i)*factorial(i)))^2
+  }
+  print(p)
+}
+cat("Routes through a 20x20 grid: ", Lattice_paths(20))
diff --git a/README.md b/README.md
index 930ec01..7421688 100644
--- a/README.md
+++ b/README.md
@@ -39,13 +39,16 @@ Happy Contributing! 😃
 | 08 | [Largest product in a series](https://projecteuler.net/problem=8)            |                    |                    |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
 | 09 | [Special Pythagorean triplet](https://projecteuler.net/problem=9)            | :white_check_mark: |                    |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
 | 10 | [Summation of primes](https://projecteuler.net/problem=10)                   |                    |                    |                    | :white_check_mark: |                    |                    | :white_check_mark: |    |                    |                     |      |       |
-| 11 | [Largest product in a grid](https://projecteuler.net/problem=11)             |                    |                    |                    | :white_check_mark:                    |                    |                    | :white_check_mark: |    |                    |                     |      |       |
+| 11 | [Largest product in a grid](https://projecteuler.net/problem=11)             |                    |                    |                    | :white_check_mark: |                    |                    | :white_check_mark: |    |                    |                     |      |       |
 | 12 | [Highly divisible triangular number](https://projecteuler.net/problem=12)    |                    |                    |                    |                    |                    |                    | :white_check_mark: |    |                    |                     |      |       |
 | 13 | [Large sum](https://projecteuler.net/problem=13)                             | :white_check_mark: |                    |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
 | 14 | [Longest Collatz sequence](https://projecteuler.net/problem=14)              |                    |                    |                    |                    |                    |                    |                    |    |                    |                     |      |       |
-| 15 | [Lattice paths](https://projecteuler.net/problem=15)                         |                    |                    |                    |                    |                    |                    |                    |    |                    |                     |      |       |
-| 16 | [Power digit sum](https://projecteuler.net/problem=16)                       |                    | :white_check_mark:|                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
-| 17 | [Number letter counts](https://projecteuler.net/problem=17)                  |                    |                    |                    |:white_check_mark:                    |                    |                    |                    |    |                    |                     |      |       |
+| 15 | [Lattice paths](https://projecteuler.net/problem=15)                         |                    |                    |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
+| 16 | [Power digit sum](https://projecteuler.net/problem=16)                       |                    | :white_check_mark: |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
+| 17 | [Number letter counts](https://projecteuler.net/problem=17)                  |                    |                    |                    |                    |                    |                    |                    |    |                    |                     |      |       |
+| 15 | [Lattice paths](https://projecteuler.net/problem=15)                         |                    |                    |                    |                    |                    |                    |                    |    |                    | :white_check_mark:  |      |       |
+| 16 | [Power digit sum](https://projecteuler.net/problem=16)                       |                    | :white_check_mark: |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
+| 17 | [Number letter counts](https://projecteuler.net/problem=17)                  |                    |                    |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |
 | 18 | [Maximum path sum I](https://projecteuler.net/problem=18)                    |                    |                    |                    |                    |                    |                    |                    |    |                    |                     |      |       |
 | 19 | [Counting Sundays](https://projecteuler.net/problem=19)                      |                    |                    |                    |                    |                    |                    |                    |    |                    |                     |      |       |
 | 20 | [Factorial digit sum](https://projecteuler.net/problem=20)                   |                    |                    |                    | :white_check_mark: |                    |                    |                    |    |                    |                     |      |       |