A094097 Number of divisor chains of length n which begin with n ("anchored" divisor chains).

1, 1, 1, 1, 1, 1, 1, 5, 4, 3, 2, 8, 4, 6, 47, 44, 6, 37, 6, 166, 462, 232, 372, 2130, 1589, 9093, 20896, 20314, 4118, 32367, 12815, 167796, 130528, 59173, 1942045, 2607312, 163775, 1297794, 18340336, 22304602, 5065878, 21005347, 3607762, 129164605

Offset: 1

Author

N. J. A. Sloane, following a suggestion of R. K. Guy, May 04 2004

Keywords

• nonn

Comments

A divisor chain of length n is an arrangement of 1..n such that each term is a divisor of the sum of the preceding terms.

Examples

			Examples of divisor chains of lengths 1 through 8:
1
2 1
3 1 2
4 2 3 1
5 1 2 4 3
6 2 4 3 5 1
7 1 2 5 3 6 4
8 2 5 3 6 4 7 1
		

Crossrefs

Cf. A067957, A094098, A094099.

Right diagonal of A093323.

Extensions

a(1)-a(9) from R. K. Guy and Paul Vaderlind

a(10)-a(19) from Ed Clark, Jr. and Chuck Seggelin

a(20)-a(28) from Christopher Landauer, May 04 2004

a(29)-a(37) from Joseph Myers, May 04 2004

a(38) from Jud McCranie, May 07 2004

a(39)-a(44) from Joseph Myers, May 21 2004