A212282 Minimal m>=1 such that n!/m-1 is prime.

1, 1, 2, 1, 1, 4, 2, 4, 5, 1, 10, 1, 4, 3, 6, 4, 8, 6, 9, 25, 4, 28, 12, 11, 9, 10, 3, 1, 2, 1, 1, 3, 34, 5, 9, 1, 35, 24, 2, 5, 3, 24, 16, 7, 5, 32, 23, 6, 13, 13, 16, 7, 6, 20, 7, 31, 6, 94, 22, 26, 78, 9, 21, 8, 15, 11, 88, 11, 7, 58, 64, 56, 16

Offset

3,3

Links

Table of n, a(n) for n=3..75.

Mathematica

a[n_] := Block[{f = n!, j=1}, While[! PrimeQ[Floor[f/j]-1], j++];
j]; v = a /@ Range[3, 75] (* Giovanni Resta, Feb 14 2013 *)

Crossrefs

Cf. A212281.

Sequence in context: A256098 A177276 A123199 * A346032 A157125 A335941

Adjacent sequences: A212279 A212280 A212281 * A212283 A212284 A212285

Keyword

nonn

Author

Vladimir Shevelev, Feb 14 2013

Extensions

a(12)-a(75) from Giovanni Resta, Feb 14 2013

Status

approved