1,3

Table of n, a(n) for n=1..74.

a(9) = 8 because 8*9!! + 1 = 8*945 + 1 = 7561 is prime.

Table[k = 0; While[!PrimeQ[k*n!! +1], k++]; k, {n, 85}]

Cf. A006882.

Sequence in context: A139813 A172009 A299150 * A339165 A129381 A319991

Adjacent sequences: A202445 A202446 A202447 * A202449 A202450 A202451

nonn

Michel Lagneau, Dec 19 2011

approved