A073692 a(0)=1; for n > 0, a(n) is the smallest odd number k such that (2 + Product_{j=a(n-1)..k-2, j odd} j) is prime.

1, 3, 5, 7, 15, 17, 19, 23, 27, 29, 31, 41, 43, 49, 69, 71, 73, 77, 79, 87, 89, 93, 97, 113, 119, 123, 127, 139, 145, 149, 151, 175, 179, 181, 187, 195, 197, 199, 213, 221, 223, 227, 229, 233, 245, 251, 263, 267, 269, 271, 285, 323, 375, 385, 389, 395, 397, 559

Offset

0,2

Links

Table of n, a(n) for n=0..57.

Mathematica

t = {}; s = 1; c = 0; Do[s = s*i; c += 1; If[PrimeQ[s + 2], AppendTo[t, i - 2*(c - 1)]; s = 1; c = 0], {i, 1, 570, 2}]; t (* Jayanta Basu, Jul 07 2013 *)

Prog

(PARI) print1("1, "); p=1; c=3; for(n=1, 80, while(!isprime(p+2), p=p*c; c=c+2); print1(c", "); p=c; c=c+2)

Crossrefs

Cf. A073691, A073693.

Sequence in context: A051445 A002181 A341845 * A132012 A160690 A085494

Adjacent sequences: A073689 A073690 A073691 * A073693 A073694 A073695

Keyword

nonn

Author

Amarnath Murthy, Aug 12 2002

Extensions

Edited by Ralf Stephan, Mar 26 2003

Status

approved