A086870 - OEIS

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A086870

Primes equal to a product of twin primes minus 1 divided by 2.

7, 17, 71, 449, 881, 2591, 9521, 39761, 106721, 179999, 206081, 342791, 388961, 596231, 847601, 1292831, 2268449, 2571911, 2836961, 3612671, 6223391, 6329681, 6415361, 8520191, 8946449, 9409121, 10342151, 12550049, 16485281, 18800711

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OFFSET

1,1

COMMENTS

From Jason Kimberley, Oct 22 2015 (Start)

Prime elements of A120876.

For each p in this list, A001221(2p) = A001222(2p) = A001221(2p+1) = A001222(2p+1) = 2.

2*a(n) is a subsequence of A103533. They first differ when 313619 is not in this sequence, but 2*313619 = 627238 = A103533(12).

(End)

LINKS

Jason Kimberley, Table of n, a(n) for n = 1..10000

FORMULA