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A137446
Positive numbers n such that n^2 +- (n-1) are primes.
2
2, 3, 4, 6, 9, 13, 15, 16, 21, 28, 39, 55, 60, 70, 76, 100, 120, 144, 148, 154, 163, 169, 174, 193, 195, 219, 246, 288, 294, 330, 343, 349, 358, 393, 396, 405, 448, 456, 490, 496, 501, 519, 541, 561, 573, 604, 606, 610, 625, 763, 769, 786, 856, 921, 994, 1023
OFFSET
1,1
EXAMPLE
2^2 +- 1 -> (3,4) Primes,
3^2 +- 2 -> (7,11) Primes,
13^2 +- 12 -> (157,181) Prime,...
MATHEMATICA
Select[Range[500], PrimeQ[ #^2-(#-1)]&&PrimeQ[ #^2+(#-1)]&]
CROSSREFS
Sequence in context: A057287 A056751 A189035 * A240028 A097557 A175848
KEYWORD
nonn
AUTHOR
EXTENSIONS
Extended by T. D. Noe, Dec 14 2008
STATUS
approved