A073870 Smallest composite number not included earlier that is a multiple of n.

4, 6, 9, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 15, 32, 34, 36, 38, 40, 21, 44, 46, 48, 25, 52, 27, 56, 58, 30, 62, 64, 33, 68, 35, 72, 74, 76, 39, 80, 82, 42, 86, 88, 45, 92, 94, 96, 49, 50, 51, 104, 106, 54, 55, 112, 57, 116, 118, 60, 122, 124, 63, 128, 65, 66, 134, 136

Offset

1,1

Comments

A permutation of the composite numbers.

Links

Table of n, a(n) for n=1..68.

Formula

It appears that for n>3, if n is an odd composite number then a(n) = n, otherwise a(n) = 2n.

Crossrefs

Cf. A073871.

Sequence in context: A343906 A180853 A085088 * A236025 A377181 A218036

Adjacent sequences: A073867 A073868 A073869 * A073871 A073872 A073873

Keyword

nonn

Author

Amarnath Murthy, Aug 16 2002

Extensions

Corrected and extended by Franklin T. Adams-Watters, May 12 2006

Edited by N. J. A. Sloane, May 05 2007

Status

approved