A072746 Number of pairs of primes (p, q) such that, for some integer k, (p+q)/2 = 2^k, 2^(k-1) < p < q, and p <= n.

0, 0, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8

Offset

1,5

Links

Table of n, a(n) for n=1..105.

Crossrefs

Cf. A072742, A072743, A071538.

Sequence in context: A209899 A111898 A279041 * A179528 A105390 A347941

Adjacent sequences: A072743 A072744 A072745 * A072747 A072748 A072749

Keyword

nonn

Author

Reinhard Zumkeller, Jul 08 2002

Extensions

Name corrected by Jon E. Schoenfield, Jun 30 2021

Status

approved