Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Check that you are only summing elements at prime numbered indices: 2,3,5,7,..
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Must be an off-by-one error. Can you post your code here? Note also that indices start at 0, not 1 (except for Fortran)