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A100712 Numbers n such that n*(n-1)-1 and n*(n+1)+1 are both primes. 1
3, 5, 6, 12, 14, 17, 20, 21, 27, 54, 57, 66, 69, 71, 77, 90, 101, 131, 141, 150, 155, 161, 164, 189, 192, 194, 231, 245, 266, 332, 336, 344, 351, 381, 392, 402, 434, 456, 476, 495, 500, 512, 531, 551, 572, 579, 582, 605, 626, 671, 677, 696, 747, 755, 762, 782, 839 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

select(n -> isprime(n*(n-1)-1) and isprime(n*(n+1)+1), [$1..1000]); # Robert Israel, Jan 04 2018

MATHEMATICA

Select[Range[6! ], PrimeQ[ #^2-(#+1)]&&PrimeQ[ #^2+(#+1)]&] (* Vladimir Joseph Stephan Orlovsky, Dec 19 2009 *)

CROSSREFS

Sequence in context: A127577 A280590 A185912 * A086187 A088082 A238961

Adjacent sequences:  A100709 A100710 A100711 * A100713 A100714 A100715

KEYWORD

easy,nonn

AUTHOR

Pierre CAMI, Dec 10 2004

EXTENSIONS

a(54)=755 inserted by Robert Israel, Jan 04 2018

STATUS

approved

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Last modified September 26 17:00 EDT 2021. Contains 347670 sequences. (Running on oeis4.)