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%I #62 Jun 30 2024 22:42:50
%S 1,4,9,22,75,172,247,666,913,2492,3405,9302,12707,22009,34716,56725,
%T 91441,148166,239607,387773,627380,1015153,1642533,2657686,4300219,
%U 6957905,11258124,18216029,29474153,47690182,77164335,124854517,202018852,326873369,528892221
%N a(1)=1, a(2)=4, and thereafter a(n) = a(n-2) + k * a(n-1), with minimal k >= 1 such that a(n) is not prime.
%e For n=5, the smallest 9 + k*22 which is not prime is a(5) = 75 at k=3.
%Y Cf. A018252, A072999.
%K nonn
%O 1,2
%A _Nicholas J. Leuchtenberg_, Jun 26 2024