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A328493
a(n) = (p_n + 1)*q_n - 1; where (p_n, q_n) is the n-th twin prime pair.
0
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
1,1
FORMULA
a(n) = A126251(n) - 1. - Michel Marcus, Oct 17 2019
EXAMPLE
For n = 2, the second twin prime pair is (5, 7). So (5 + 1) * 7 - 1 = 41 is the second term.
MATHEMATICA
(#[[1]]+1)#[[2]]-1&/@Select[Partition[Prime[Range[300]], 2, 1], #[[2]]- #[[1]] == 2&] (* Harvey P. Dale, Aug 30 2021 *)
PROG
(PARI) my(p = 3); forprime(n=5, 2000, if(n - p == 2, print1((p + 1)*n - 1, ", ")); p=n)
CROSSREFS
KEYWORD
nonn
AUTHOR
Dimitris Valianatos, Oct 16 2019
STATUS
approved