A319410 Twice A032741.

0, 0, 2, 2, 4, 2, 6, 2, 6, 4, 6, 2, 10, 2, 6, 6, 8, 2, 10, 2, 10, 6, 6, 2, 14, 4, 6, 6, 10, 2, 14, 2, 10, 6, 6, 6, 16, 2, 6, 6, 14, 2, 14, 2, 10, 10, 6, 2, 18, 4, 10, 6, 10, 2, 14, 6, 14, 6, 6, 2, 22, 2, 6, 10, 12, 6, 14, 2, 10, 6, 14, 2, 22, 2, 6, 10, 10, 6, 14, 2, 18, 8, 6, 2, 22, 6, 6, 6, 14, 2, 22, 6, 10, 6, 6, 6, 22, 2, 10, 10, 16

Offset

0,3

Comments

For n>0, twice the number of proper divisors of n (d|n, d<n).

Links

Table of n, a(n) for n=0..100.

Claude Lenormand, Deux transformations sur les mots, Preprint, 5 pages, Nov 17 2003. Apparently unpublished. This is a scanned copy of the version that the author sent to me in 2003.

Crossrefs

Cf. A032741.

A column of the triangle in A319411.

Sequence in context: A073348 A287093 A122457 * A337174 A139770 A140635

Adjacent sequences: A319407 A319408 A319409 * A319411 A319412 A319413

Keyword

nonn

Author

N. J. A. Sloane, Sep 20 2018

Status

approved