A074931 - OEIS

A074931

Primes p such that 3p is equidistant from consecutive prime twin pairs.

3, 5, 17, 29, 41, 71, 149, 281, 317, 347, 359, 397, 647, 751, 787, 857, 907, 1093, 1279, 1381, 1511, 1531, 1663, 1783, 2447, 2683, 2803, 3271, 3323, 4019, 4153, 4513, 4567, 4639, 5557, 5647, 5801, 5923, 6599, 6659, 6911, 7013, 7573, 7883, 9187, 9257, 9431

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OFFSET

1,1

COMMENTS

Numbers equidistant from consecutive twins (see A074953) are multiples of 3 and they may be almost primes only of form 3*prime. In the sequence, these primes are given. Also: A001748 (3*prime 2-almost-primes) and A001358 (all 2-almost-primes).

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

17 is in the sequence because 3 * 17 = 51 is equidistant between {41, 43} and {59, 61}.

19 is not in the sequence because 3 * 19 = 57, which is much closer to {59, 61} than to {41, 43}.

CROSSREFS

Cf. A001358, A001748, A074953.

Sequence in context: A038703 A283806 A163586 * A023226 A113169 A350856

Adjacent sequences: A074928 A074929 A074930 * A074932 A074933 A074934

KEYWORD

nonn

AUTHOR

N. Fernandez (primeness(AT)borve.org), Zak Seidov, Oct 10 2002

EXTENSIONS

New name from Charles R Greathouse IV, Oct 12 2013

STATUS

approved