A334142 Indices of twin primes.

2, 3, 4, 5, 6, 7, 8, 10, 11, 13, 14, 17, 18, 20, 21, 26, 27, 28, 29, 33, 34, 35, 36, 41, 42, 43, 44, 45, 46, 49, 50, 52, 53, 57, 58, 60, 61, 64, 65, 69, 70, 81, 82, 83, 84, 89, 90, 98, 99, 104, 105, 109, 110, 113, 114, 116, 117, 120, 121, 140, 141, 142, 143, 144, 145, 148, 149

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Twin Primes.

Formula

a(n) = A000720(A001097(n)).

Set union of A029707 and A107770.

Maple

q:= n-> (p-> isprime(p-2) or isprime(p+2))(ithprime(n)):
select(q, [$1..150])[];  # Alois P. Heinz, Apr 15 2020

Mathematica

With[{p = PositionIndex[(#[[2]] - #[[1]] - 2) & /@ Partition[Prime[Range[150]], 2, 1]][0]}, Union[p, p + 1]] (* Amiram Eldar, Sep 06 2024 *)

Crossrefs

Cf. A000720, A001097, A029707, A107770.

Sequence in context: A132018 A369003 A377869 * A044919 A011871 A377357

Adjacent sequences: A334139 A334140 A334141 * A334143 A334144 A334145

Keyword

nonn

Author

Ilya Gutkovskiy, Apr 15 2020

Status

approved