diff --git a/fortran/src/p0020.f90 b/fortran/src/p0020.f90
index 5bb73497..8ffb2f82 100644
--- a/fortran/src/p0020.f90
+++ b/fortran/src/p0020.f90
@@ -13,7 +13,7 @@ module Problem0020
     use constants
     implicit none
 contains
-    pure integer function p0020() result(answer)
+    pure integer(i18t) function p0020() result(answer)
         integer(i18t), dimension(10) :: numbers
         integer(i18t) :: power
         integer :: i, j
diff --git a/lua/src/p0020.lua b/lua/src/p0020.lua
index fd5b150a..0e13b283 100644
--- a/lua/src/p0020.lua
+++ b/lua/src/p0020.lua
@@ -26,7 +26,7 @@ return {
                 end
             end
         end
-        for i = 1,16 do
+        for _ = 1,16 do
             for j = 1,#numbers do
                 answer = answer + math.floor(numbers[j] / power) % 10
             end