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%I #10 Feb 14 2021 08:15:01
%S 2,3,5,7,15,19,41,59,61,105,661,2653,3069,3943,4053
%N Numbers k such that 1 + Sum_{j=0..k} (-1)^j*(k-j)! is prime.
%C Note that when k is even, 3 divides the sum.
%C The sums corresponding to terms >= 661 are only probable primes. - _Klaus Brockhaus_, Mar 13 2009
%e a(2) = ((-1)^0)(2-0)! + ((-1)^1)(2-1)! + ((-1)^2)(2-2)! + 1 = 2! - 1! + 0! + 1 = 3 (prime).
%K nonn,more
%O 1,1
%A _Kyle D. Balliet_, Mar 07 2009
%E a(7)-a(15) from _Klaus Brockhaus_, Mar 13 2009
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