A220141 Prime numbers p that yield a new record for the least number k such that p*k + 1 and p*k - 1 are twin primes.

2, 5, 11, 13, 31, 37, 53, 61, 433, 3023, 3989, 4079, 9967, 10789, 76943, 81439, 121763, 233969, 491333, 495931, 795659, 1653901, 2623969, 3516277, 6274823, 10536689, 11313839, 12023191, 16268899, 22829309, 38968109, 41230733, 45057577, 76384717, 98566373, 552843883

Offset

1,1

Comments

These are the primes at which A071407 reaches a new record. The corresponding values of k are in A220142.

Links

Amiram Eldar, Table of n, a(n) for n = 1..38

Mathematica

t = {{2, 2}}; Do[k = 1; While[! (PrimeQ[k*n - 1] && PrimeQ[k*n + 1]), k++]; If[k > t[[-1, 2]], AppendTo[t, {n, k}]], {n, Prime[Range[2, 1000]]}]; Transpose[t][[1]]

Crossrefs

Cf. A071407, A220142.

Sequence in context: A062572 A215214 A221868 * A106283 A020629 A355657

Adjacent sequences: A220138 A220139 A220140 * A220142 A220143 A220144

Keyword

nonn

Author

T. D. Noe, Jan 08 2013

Extensions

More terms from Amiram Eldar, Dec 30 2019

Status

approved