A055224 a(1) = 1, a(n) = number of a(k) with 1 <= k <= n-1 such that a(k) divides a(n-k).

1, 1, 2, 2, 2, 3, 4, 5, 4, 4, 3, 5, 4, 5, 3, 6, 7, 4, 5, 8, 6, 9, 6, 5, 6, 9, 10, 8, 5, 6, 10, 9, 8, 6, 6, 10, 11, 12, 9, 8, 13, 5, 11, 8, 8, 11, 6, 15, 7, 14, 11, 5, 13, 13, 10, 10, 5, 13, 8, 14, 10, 7, 12, 13, 13, 12, 8, 11, 12, 9, 12, 14, 12, 8, 8, 15, 15, 12, 14, 12, 14, 15, 13, 19, 15, 12

Offset

1,3

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Example

a(10) = 4 because a(1)|a(9), a(2)|a(8), a(3)|a(7), a(5)|a(5).

Prog

(PARI) a = vector(86); for (n=1, #a, a[n] = if (n==1, 1, sum(k=1, n-1, a[n-k]%a[k]==0)); print1 (a[n] ", ")) \\ Rémy Sigrist, Jul 27 2018

Crossrefs

Sequence in context: A275446 A306271 A144732 * A126295 A266686 A323259

Adjacent sequences: A055221 A055222 A055223 * A055225 A055226 A055227

Keyword

nonn

Author

Leroy Quet, Jun 20 2000

Extensions

More terms from James A. Sellers, Jul 04 2000

Status

approved