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A213107
Primes p such that 2p^2-1, 3p^2-2, 4p^2-3, and 5p^2-4 are also prime.
6
17569, 43781, 70321, 229561, 251231, 426131, 426551, 453289, 635051, 727201, 729791, 741709, 944689, 981091, 1015309, 1078081, 1128761, 1228429, 1231229, 1282961, 1289149, 1302349, 1351099, 1723481, 1763159, 1823779, 2078339, 2260889, 2336519, 2357879
OFFSET
1,1
COMMENTS
Subsequence of A213079: a(1) = 17569 = A213079(10) =A213078(44)= A106483(389) = A000040(2019).
LINKS
MATHEMATICA
Select[Prime[Range[200000]], PrimeQ[2 #^2 - 1] && PrimeQ[3 #^2 - 2] && PrimeQ[4 #^2 - 3] && PrimeQ[5 #^2 - 4] &] (* T. D. Noe, Jun 06 2012 *)
PROG
(Magma) [p: p in PrimesUpTo(2500000) | forall{i*p^2-i+1: i in [2..5] | IsPrime(i*p^2-i+1)}]; // Vincenzo Librandi, Apr 08 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Jun 05 2012
STATUS
approved