The On-Line Encyclopedia of Integer Sequences (OEIS)

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A144730

a(n) is the smallest positive integer m such that b * (Product_{k=1..n} a(k)) + 1 is prime, with b = 7.
(history; published version)

#5 by N. J. A. Sloane at Fri Jun 18 15:25:46 EDT 2021

STATUS

proposed

approved

#4 by Georg Fischer at Fri Jun 18 15:02:06 EDT 2021

STATUS

editing

proposed

#3 by Georg Fischer at Fri Jun 18 15:01:54 EDT 2021

NAME

a(n)= is the smallest positive integer k m such that a(0)b *a (Product_{k=1)*a(2)*...*n} a(nk)) + 1 is prime. a(0), with b = 7.

CROSSREFS

A046966, A046972, A144717, A144718, A144722, A144723, A144724, A144725, A144726, A144727, A144728, A144729, A144730, A144731

EXTENSIONS

Definition corrected by Georg Fischer, Jun 18 2021

STATUS

approved

editing

#2 by Russ Cox at Sat Mar 31 10:22:09 EDT 2012

AUTHOR

_Artur Jasinski (grafix(AT)csl.pl), _, Sep 19 2008

Discussion

Sat Mar 31

10:22

OEIS Server: https://oeis.org/edit/global/339

#1 by N. J. A. Sloane at Fri Jan 09 03:00:00 EST 2009

NAME

a(n)= smallest positive integer k such that a(0)*a(1)*a(2)*...*a(n) + 1 is prime. a(0)=7

DATA

4, 7, 13, 19, 33, 35, 36, 43, 48, 55, 59, 62, 87, 129, 149, 153, 159, 190, 228, 231, 245, 265, 266, 269, 284, 300, 329, 331, 340, 347, 372, 432, 449, 450, 461, 485, 496, 500, 514, 544, 560, 565, 594, 598, 605, 614, 639, 677, 684, 734, 736, 794, 804, 813, 882

OFFSET

1,1

MATHEMATICA

k = 7; a = {}; Do[If[PrimeQ[k n + 1], k = k n; AppendTo[a, n]], {n, 1, 3000}]; a (*Artur Jasinski*)

CROSSREFS

A046966, A046972, A144717, A144718, A144722, A144723, A144724, A144725, A144726, A144727, A144728, A144729, A144730, A144731

KEYWORD

nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Sep 19 2008

STATUS

approved