A125767 - OEIS

A125767

Least prime of the form n*T_i +/-1, where T is a triangular number.

2, 3, 2, 3, 29, 5, 41, 7, 53, 11, 67, 11, 79, 13, 89, 17, 101, 17, 113, 19, 127, 23, 137, 23, 149, 79, 163, 29, 173, 29, 311, 31, 197, 101, 211, 37, 223, 37, 233, 41, 409, 41, 257, 43, 269, 47, 281, 47, 293, 149, 307, 53, 317, 53, 331, 167, 569, 59, 353, 59, 367, 61, 379

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..63.

MATHEMATICA

f[n_] := Block[{k = 1, s = {}, trnglr}, While[s == {}, trnglr = n*k(k + 1)/2; If[PrimeQ[trnglr - 1], AppendTo[s, trnglr - 1]]; If[PrimeQ[trnglr + 1], AppendTo[s, trnglr + 1]]; k++ ]; s[[1]]]; Array[f, 63]

CROSSREFS

Cf. A000217, A125765, A125766, A125768, A125769.

Sequence in context: A282049 A038700 A177799 * A326991 A131580 A087038

Adjacent sequences: A125764 A125765 A125766 * A125768 A125769 A125770

KEYWORD

nonn

AUTHOR

Jonathan Vos Post & Robert G. Wilson v, Dec 01 2006

STATUS

approved