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 A182091 Numbers n such that (n-1)*n^2/2-1 is prime. 0
 4, 6, 8, 10, 13, 17, 18, 21, 22, 25, 30, 34, 36, 38, 41, 42, 45, 46, 56, 57, 58, 62, 64, 69, 70, 72, 74, 86, 88, 101, 105, 113, 114, 116, 120, 122, 126, 132, 133, 141, 157, 158, 174, 176, 181, 182, 186, 192, 198, 200, 205, 216, 217, 221, 224, 240, 253, 254 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(1)=4 because (4-1)*4^2/2-1=23 is prime, a(2)=6 because (6-1)*6^2/2-1=89 is prime. MATHEMATICA Select[Range[300], PrimeQ[(# - 1)*#^2/2 - 1] &] (* T. D. Noe, Apr 11 2012 *) CROSSREFS Cf. A006002. Sequence in context: A189473 A189383 A087684 * A084808 A031020 A087270 Adjacent sequences:  A182088 A182089 A182090 * A182092 A182093 A182094 KEYWORD nonn AUTHOR Gerasimov Sergey, Apr 11 2012 STATUS approved

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