

A120395


Let p(1) = 13. Then a(n) is the least k such that p(n+1) = (k*p(n))^2 + k*p(n)  1 is prime.


4



1, 1, 4, 4, 10, 1, 351, 240, 620, 1362, 2184, 46, 2944
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OFFSET

1,3


COMMENTS

p sequence starts 181, 32941, 17361883459, 4822959955971812408731, ...
a(13) corresponds to a 12,272digit BPSWprobable prime.  Charles R Greathouse IV, Apr 22 2012


LINKS

Table of n, a(n) for n=1..13.


PROG

(PARI) p=13; for(i=1, 9, k=1; while(!ispseudoprime(t=(k*p)^2+k*p1), k++); p=t; print1(k", ")) \\ Charles R Greathouse IV, Apr 20 2012


CROSSREFS

Sequence in context: A091016 A198025 A205549 * A321078 A160723 A255486
Adjacent sequences: A120392 A120393 A120394 * A120396 A120397 A120398


KEYWORD

nonn


AUTHOR

Pierre CAMI, Jul 01 2006


EXTENSIONS

a(9)a(12) from Charles R Greathouse IV, Apr 20 2012
a(13) from Charles R Greathouse IV, Apr 22 2012


STATUS

approved



