%I #4 Mar 30 2012 18:40:28
%S 2,3,1,4,1,3,7,2,5,10,1,2,5,6,5,2,7,6,11,6,3,5,3,7,11,2,3,2,9,10,7,5,
%T 5,5,5,2,1,2,5,2,3,2,5,4,9,4,3,2,5,11,3,11,3,3,5,7,1,4,3,4,11,4,5,16,
%U 7,2,7,2,3,25,9,6,5,2,5,2,5,2,5,4,17,20,7,4,5,4,15,2,5,6,7,6,3,5,1,2,5,8,3
%N Minimal value of k>0 such that n^6 + k^2 is a semiprime.
%C It seems that one or more primes nearly always occur before finding the first such semiprime for a given n. There seems to be a high correlation with the n^5 + k^2 sequence (A109200) [such as n=63] and it with the n^2 + k^2 sequence (A109197).
%F a(n) = minimal value of k>0 such that n^6 + k^2 is semiprime.
%e a(0) = 2 because 0^6 + 1^2 = 1 is not semiprime, but 0^6 + 2^2 = 4 = 2^2 is.
%e a(1) = 3 because 1^6 + 1^2 and 1^6 + 2^2 are not semiprime, but 1^6 + 3^2 = 10 = 2 * 5 is semiprime.
%e a(2) = 1 because 2^6 + 1^2 = 65 = 5 * 13 is semiprime.
%e a(69) = 25 because 69^6 + 25^2 = 107918163706 = 2 * 53959081853 and for no smaller k>0 is 69^6 + k^2 a semiprime.
%e a(100) = 7 because 100^6 + 7^2 = 1000000000049 = 6337 * 157803377 and for no smaller k>0 is 100^6 + k^2 a semiprime.
%Y Cf. A001358, A108714, A109197, A109198, A109199, A109200.
%K easy,nonn
%O 0,1
%A _Jonathan Vos Post_, Jun 29 2005