A168563 a(n) = (n-th prime > 3) minus (n-th composite number).

1, 1, 3, 4, 7, 7, 9, 14, 15, 19, 21, 22, 25, 29, 34, 35, 40, 43, 43, 47, 50, 55, 62, 65, 65, 68, 69, 71, 83, 86, 91, 91, 100, 101, 106, 111, 113, 118, 123, 124, 133, 133, 135, 136, 147, 158, 161, 161, 164, 169, 169, 177, 182, 187, 192, 193, 197, 200, 201, 209, 222, 225, 226

Offset

1,3

Links

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

Formula

a(n) = prime(n+2)-composite(n) = A161671(n+2).

Mathematica

Module[{nn=100, pr, cmp}, cmp=Select[Range[nn], CompositeQ]; pr=Prime[ Range[ 3, Length[cmp]+2]]; pr-cmp] (* Harvey P. Dale, May 28 2015 *)

Crossrefs

Cf. A161671.

Sequence in context: A162431 A024605 A215630 * A261368 A307743 A257007

Adjacent sequences: A168560 A168561 A168562 * A168564 A168565 A168566

Keyword

nonn,easy

Author

Juri-Stepan Gerasimov, Nov 29 2009

Extensions

Edited by Charles R Greathouse IV, Mar 25 2010

Status

approved