A057130 Product of first n primes of form 6k-1.

5, 55, 935, 21505, 623645, 25569445, 1201763915, 63693487495, 3757915762205, 266812019116555, 22145397586674065, 1970940385213991785, 199064978906613170285, 21299952743007609220495, 2406894659959859841915935, 315303200454741639290987485

Offset: 1

Author

Henry Bottomley, Aug 11 2000

Keywords

• nonn
• easy

Examples

			a(3) = 5*11*17 = 935.
a(4) = 21505 = 5 * 11 * 17 * 23.
		

Crossrefs

Cf. A000040, A002110, A002476, A006278, A007528, A074040, A078586, A121940.

Cf. A008543, A057131.

Programs

PARI

lista(nn) = {pp = 1; for (n = 1, nn, p = prime(n); if (Mod(p, 6) == -1, pp *= p; print1(pp, ", ")););} \\ Michel Marcus, Sep 08 2013

Formula

a(n) = a(n-1)*A007528(n) = (A057131(n)+1)/6.

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Oct 06 2000

More terms from Michel Marcus, Sep 08 2013