A093003 Number of composite numbers among next n numbers.

0, 0, 2, 3, 3, 4, 6, 6, 6, 8, 9, 9, 10, 11, 12, 14, 13, 15, 16, 16, 17, 18, 19, 20, 21, 22, 23, 23, 24, 24, 27, 27, 30, 28, 29, 29, 32, 33, 33, 36, 33, 37, 37, 38, 37, 40, 39, 43, 42, 45, 40, 48, 47, 45, 48, 48, 48, 50, 52, 53, 52, 55, 55, 57, 53, 61, 58, 59, 58, 61, 64, 65, 61

Offset

1,3

Links

Table of n, a(n) for n=1..73.

Formula

comp(n(n+1)/2) - comp(n(n-1)/2), where comp(m) = number of composite numbers less than or equal to m.

Example

a(5) = 3, among 11,12,13,14,15 there are three composite numbers 12,14 and 15.

Crossrefs

Cf. A093004.

Sequence in context: A239964 A290585 A106464 * A348540 A118096 A296440

Adjacent sequences: A093000 A093001 A093002 * A093004 A093005 A093006

Keyword

nonn

Author

Amarnath Murthy, Mar 29 2004

Extensions

Corrected and extended by Joshua Zucker, May 08 2006

Status

approved