A137722 Number of numbers not greater than n with exactly one prime gap in their factorization.

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 7, 8, 9, 9, 9, 9, 10, 11, 12, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 17, 18, 18, 18, 19, 20, 21, 22, 22, 22, 22, 23, 24, 24, 25, 26, 26, 27, 28, 29, 29, 29, 29, 30, 30, 31, 31, 32, 32, 33, 33, 34

Offset

1,14

Comments

a(n) > a(n-1) iff A073490(n) = 1;

A137721(n) > a(n) for n < 134;

A137721(n) < a(n) for n > 140.

Links

R. Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A073493.

Sequence in context: A103374 A208251 A241087 * A081305 A035665 A352829

Adjacent sequences: A137719 A137720 A137721 * A137723 A137724 A137725

Keyword

nonn

Author

Reinhard Zumkeller, Feb 09 2008

Status

approved