A175511 n-th even semiprime minus n-th semiprime.

0, 0, 1, 4, 8, 11, 13, 16, 21, 32, 29, 40, 47, 48, 55, 60, 69, 71, 79, 85, 88, 96, 101, 109, 120, 125, 124, 129, 132, 139, 163, 169, 180, 183, 192, 191, 199, 208, 215, 225, 236, 239, 253, 253, 260, 257, 280, 303, 309, 312, 311, 320, 323, 341, 348, 357, 361, 364

Offset

1,4

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n)=A100484(n)-A001358(n).

Mathematica

Module[{sps=Select[Range[600], PrimeOmega[#]==2&], evs}, evs= Select[ sps, EvenQ]; #[[1]]-#[[2]]&/@Thread[{evs, Take[sps, Length[evs]]}]] (* Harvey P. Dale, Sep 07 2012 *)

Crossrefs

Cf. A131634.

Sequence in context: A311022 A311023 A311024 * A311025 A311026 A311027

Adjacent sequences: A175508 A175509 A175510 * A175512 A175513 A175514

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jun 03 2010

Extensions

Entries checked by R. J. Mathar, Aug 12 2010

Status

approved