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%I #7 Oct 04 2017 14:02:47
%S 1,2,1,4,1,3,1,3,2,2,1,3,1,3,2,2,1,3,1,3,2,2,1,3,2,2,2,2,1,3,1,3,2,2,
%T 2,2,1,3,2,2,1,3,1,3,2,2,1,3,2,2,2,2,1,3,2,2,2,2,1,3,1,3,2,2,2,2,1,3,
%U 2,2,1,3,1,3,2,2,2,2,1,3,2,2,1,3,2,2,2,2,1,3,2,2,2,2,2,2,1,3,2,2,1,3,1,3,2
%N a(n) = least k > 0 such that n-th partial sum is divisible by n if and only if n is not prime.
%H Antti Karttunen, <a href="/A095248/b095248.txt">Table of n, a(n) for n = 1..10000</a>
%e n = 1 is not prime, k = 1 results in first partial sum 1 divisible by 1 as required, so a(1) = 1.
%e n = 2 is prime, k = 1 results in second partial sum 2 divisible by 2 and is excluded, but k = 2 results in second partial sum 3 not divisible by 2 as required, so a(2) = 2.
%o (PARI) {m=105;s=0;for(n=1,m,k=1;if(isprime(n), while((s+k)%n==0,k++), while((s+k)%n>0,k++));print1(k,",");s=s+k)}
%K nonn
%O 1,2
%A _Amarnath Murthy_, Jun 17 2004
%E Edited and extended by _Klaus Brockhaus_, Jun 19 2004
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