A328493 a(n) = (p_n + 1)*q_n - 1; where (p_n, q_n) is the n-th twin prime pair.
19, 41, 155, 341, 929, 1805, 3659, 5255, 10505, 11771, 19181, 22649, 32579, 37055, 39401, 52211, 57839, 73169, 79805, 97655, 121451, 176819, 187055, 213905, 273005, 325469, 360599, 382541, 412805, 436259, 656909, 676505, 686411, 737021, 778805, 1041419, 1066055, 1103549, 1128905
Offset: 1
Keywords
Examples
For n = 2, the second twin prime pair is (5, 7). So (5 + 1) * 7 - 1 = 41 is the second term.
Programs
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Mathematica
(#[[1]]+1)#[[2]]-1&/@Select[Partition[Prime[Range[300]],2,1],#[[2]]- #[[1]] == 2&] (* Harvey P. Dale, Aug 30 2021 *)
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PARI
my(p = 3); forprime(n=5, 2000, if(n - p == 2, print1((p + 1)*n - 1, ", ")); p=n)
Formula
a(n) = A126251(n) - 1. - Michel Marcus, Oct 17 2019