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Revision History for A057130 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

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Product of first n primes of form 6k-1.
(history; published version)
#6 by Bruno Berselli at Sun Sep 08 02:55:33 EDT 2013
STATUS

proposed

approved

#5 by Michel Marcus at Sun Sep 08 00:38:56 EDT 2013
STATUS

editing

proposed

#4 by Michel Marcus at Sun Sep 08 00:38:48 EDT 2013
DATA

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

FORMULA

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

EXAMPLE

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

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

EXTENSIONS

More terms from Michel Marcus, Sep 08 2013

STATUS

approved

editing

#3 by Russ Cox at Fri Mar 30 18:51:28 EDT 2012
AUTHOR

_Henry Bottomley (se16(AT)btinternet.com), _, Aug 11 2000

Discussion
Fri Mar 30
18:51
OEIS Server: https://oeis.org/edit/global/247
#2 by N. J. A. Sloane at Fri May 11 03:00:00 EDT 2007
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.

KEYWORD

nonn,easy,new

#1 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003
NAME

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

DATA

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

OFFSET

1,1

FORMULA

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

EXAMPLE

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

CROSSREFS
KEYWORD

nonn,easy

AUTHOR

Henry Bottomley (se16(AT)btinternet.com), Aug 11 2000

EXTENSIONS

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

STATUS

approved