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f=->s,n{[s,l=(2..).find{|d|~s%d<1}][n]||f[l*s,n-1]} (2..), the infinite range starting from 2, isn't supported on TIO yet.
This is a recursive function that takes a starting value s (can be a prime or composite), returns it when n=0 (edit: note that this means it's zero-indexed), returns the least number l that's greater than 1 and divides -(s+1) when n=1, and otherwise recurses with s=l*s and n=n-1.
f=->s,n{[s,l=(2..).find{|d|~s%d<1}][n]||f[l*s,n-1]} (2..), the infinite range starting from 2, isn't supported on TIO yet.
This is a recursive function that takes a starting value s (can be a prime or composite), returns it when n=0, returns the least number l that's greater than 1 and divides -(s+1) when n=1, and otherwise recurses with s=l*s and n=n-1.
f=->s,n{[s,l=(2..).find{|d|~s%d<1}][n]||f[l*s,n-1]} (2..), the infinite range starting from 2, isn't supported on TIO yet.
This is a recursive function that takes a starting value s (can be a prime or composite), returns it when n=0 (edit: note that this means it's zero-indexed), returns the least number l that's greater than 1 and divides -(s+1) when n=1, and otherwise recurses with s=l*s and n=n-1.
f=->s,n{[s,l=(2..).find{|d|~s%d<1}][n]||f[l*s,n-1]} (2..), the infinite range starting from 2, isn't supported on TIO yet.
This is a recursive function that takes a starting value s (can be a prime or composite), returns it when n=0, returns the least number l that's greater than 1 and divides -(s+1) when n=1, and otherwise recurses with s=l*s and n=n-1.