A206762 a(n) is the least number from 1,2,...,n-1, such that n!/a(n)+1 is prime, and a(n)=0, if such number does not exist.

1, 1, 2, 2, 3, 2, 2, 5, 6, 1, 8, 2, 5, 7, 2, 3, 0, 5, 8, 4, 16, 3, 8, 4, 10, 1, 13, 8, 2, 19, 4, 11, 11, 7, 3, 1, 12, 13, 4, 1, 24, 2, 8, 5, 9, 25, 16, 2, 12, 0, 26, 0, 17, 22, 44, 22, 37, 7, 48, 4, 37, 18, 7, 39, 16, 19, 7, 15, 19, 36, 30, 1, 14, 15, 16, 1

Offset

2,3

Comments

The sequence of primes n!/a(n)+1, when a(n)>0, is increasing.

Links

Table of n, a(n) for n=2..77.

Mathematica

Table[s = Select[Range[n - 1], PrimeQ[n!/# + 1] &, 1]; If[s == {}, 0, s[[1]]], {n, 2, 100}] (* T. D. Noe, Feb 13 2012 *)

Crossrefs

Cf. A089136, A092265, A092965, A092969, A092970.

Sequence in context: A343534 A275383 A351627 * A212281 A225637 A185268

Adjacent sequences: A206759 A206760 A206761 * A206763 A206764 A206765

Keyword

nonn

Author

Vladimir Shevelev, Feb 12 2012

Status

approved