A112273 A puzzle sequence, answer unknown.

5, 15, 365, 945

Offset

1,1

Comments

Possible solution is a(1) = 5; a(n) = 5 + 5 * n * A215148(n-1), giving 5, 15, 365, 945, 1755, 2795, 4065, 5565, 7295, 9255, 11445, 13865, 16515, 19395, ... . - Michal Paulovic, Sep 15 2023

Links

Table of n, a(n) for n=1..4.

Floor en Lyanne van Lamoen, puzzle sequences from "Ask Dr. Math". Nov 28, 2005.

Crossrefs

Cf. A215148.

Sequence in context: A053926 A216463 A213147 * A298510 A371887 A318898

Adjacent sequences: A112270 A112271 A112272 * A112274 A112275 A112276

Keyword

nonn,unkn

Author

N. J. A. Sloane, Nov 24 2005

Status

approved