A396644 Number of cousin primes < 2^n.

0, 0, 1, 2, 4, 6, 11, 16, 27, 42, 65, 109, 173, 304, 501, 860, 1518, 2678, 4749, 8500, 15320, 27765, 50326, 91996, 168285, 309294, 571477, 1057147, 1962048, 3650516, 6810112, 12740284, 23875506, 44842400, 84384850, 159089621, 300415965, 568225074, 1076428659

Offset

1,4

Comments

Only the upper prime of each pair is counted, e.g. the pair (7,11) is counted in a(4), not a(3).

Links

Benjamin Chaffin, Table of n, a(n) for n = 1..63

Crossrefs

Cf. A080840, A007053, A033843, A341843.

Sequence in context: A115269 A103692 A114921 * A103442 A238375 A056342

Adjacent sequences: A396641 A396642 A396643 * A396645 A396647 A396648

Keyword

nonn

Author

Benjamin Chaffin, Jun 01 2026

Status

approved