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A217841 Fermat pseudoprimes n to base 3 for which sqrt(8*n + 1) is an integer. 2
91, 703, 1891, 2701, 7381, 8911, 10585, 12403, 16471, 18721, 29161, 38503, 41041, 49141, 79003, 88831, 93961, 104653, 115921, 146611, 188191, 218791, 226801, 269011, 286903, 314821, 334153, 364231, 385003, 497503, 534061, 597871, 665281, 721801, 736291, 765703, 873181, 954271, 1056331, 1237951 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Fermat Pseudoprime

PROG

(PARI) list(lim)=my(v=List(), n); lim\=1; forstep(k=27, sqrtint(8*lim+1), 2, n=k^2>>3; if(Mod(3, n)^(n-1)==1, listput(v, n))); Vec(v) \\ Charles R Greathouse IV, Jun 30 2017

CROSSREFS

Cf. A005935, A210461 (subsequence).

Sequence in context: A188360 A165220 A020218 * A084319 A047696 A043459

Adjacent sequences:  A217838 A217839 A217840 * A217842 A217843 A217844

KEYWORD

nonn

AUTHOR

Marius Coman, Oct 12 2012

EXTENSIONS

a(15)-a(18) and a(35) from Charles R Greathouse IV, Jun 30 2017

STATUS

approved

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Last modified August 12 05:33 EDT 2020. Contains 336438 sequences. (Running on oeis4.)