A057130 - OEIS

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..16.

FORMULA

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

EXAMPLE

a(3) = 5*11*17 = 935.

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

PROG

(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

CROSSREFS

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

Cf. A008543, A057131.

Sequence in context: A365588 A367164 A008543 * A141357 A357394 A093352

Adjacent sequences: A057127 A057128 A057129 * A057131 A057132 A057133

KEYWORD

nonn,easy

AUTHOR

Henry Bottomley, Aug 11 2000

EXTENSIONS

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

More terms from Michel Marcus, Sep 08 2013

STATUS

approved