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%I #13 Apr 03 2015 17:49:09
%S 1,1,5,1,1,2,1,0,1,0,0,1,5,1,0,0,1,5,1,0,5,1,5,1,1,0,0,0,1,1,0,1,0,1,
%T 1,0,0,5,1,0,0,1,0,0,0,0,1,5,0,1,5,2,0,0,0,2,0,0,0,1,0,2,5,0,1,2,0,0,
%U 1,1,0,1,0,0,0,2,0,0,1,0,5,1,0,1,1,2,1
%N Smallest k>=1 such that n^2 + (n+1)^2 + ... + (n+k)^2 is prime or a(n)=0 if there is no such k.
%C Every term is either 0 or 1 or 2 or 5.
%C a(n)=0 if and only if n is in A256385.
%F 1) if 2n^2+2n+1 is prime, then a(n)=1;
%F 2) if 2n^2+2n+1 is not prime, but 3n^2+6n+5 is prime, then a(n)=2;
%F 3) if 2n^2+2n+1 and 3n^2+6n+5 are both composite numbers, but 6n^2+30n+55 is prime, then a(n)=5;
%F 4) otherwise, a(n)=0.
%Y Cf. A000290, A256385, A089306.
%K nonn
%O 1,3
%A _Vladimir Shevelev_, Mar 31 2015
%E More terms from _Peter J. C. Moses_, Mar 31 2015
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