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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. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 7 12:58 EST 2023. Contains 360123 sequences. (Running on oeis4.)