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Least k>0 such that k!*n!+1 is a prime, or 0 if no such k exists.
2

%I #13 Nov 18 2013 15:29:59

%S 1,1,1,4,2,8,3,3,3,4,1,2,3,5,8,4,10,2,11,9,5,5,7,3,14,18,1,40,24,5,5,

%T 18,8,20,2,49,1,3,5,28,1,17,38,27,11,16,10,3,24,270,2,45,2,15,175,64,

%U 17,6,4,3,8,18,13,17,65,32,12,7,72,13,21,33,1,24,36,76,1

%N Least k>0 such that k!*n!+1 is a prime, or 0 if no such k exists.

%C Indices of 1's: A002981.

%t Table[k = 1; While[! PrimeQ[k!*n! + 1], k++]; k, {n, 100}] (* _T. D. Noe_, Nov 18 2013 *)

%Y Cf. A002981, A035093, A057217, A075757, A075758, A231901.

%K nonn

%O 1,4

%A _Alex Ratushnyak_, Nov 15 2013