A092927 Smallest prime of the form n(n-1)(n-2)...(n-k)+1, or 0 if no such prime exists.

2, 3, 7, 5, 61, 7, 43, 337, 73, 11, 991, 13, 157, 121080961, 211, 17, 14820309504001, 19, 0, 6841, 421, 23, 10627, 96909121, 601, 15601, 17551, 29, 173059286401, 31, 530122321, 29761, 3569119343741952001, 1123, 25622035084801, 37

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..968

Example

a(8) = 8*7*6 +1 = 337.

Mathematica

Flatten[Table[Select[Rest[FoldList[Times, 1, Range[n, 1, -1]]]+1, PrimeQ, 1]/. {}->{0}, {n, 40}]] (* Harvey P. Dale, Jul 10 2012 *)

Prog

(PARI) f(n, k)=prod(i=n-k, n, i)+1; a(n)=for (i=0, n, if(isprime(f(n, i)), print1(f(n, i)); break()))

Crossrefs

Cf. A092925, A092926, A092928.

Sequence in context: A353075 A069587 A059843 * A071553 A021812 A155891

Adjacent sequences: A092924 A092925 A092926 * A092928 A092929 A092930

Keyword

nonn

Author

Amarnath Murthy, Mar 18 2004

Extensions

More terms from Mohammed Bouayoun (bouyao(AT)wanadoo.fr), Mar 19 2004

Status

approved