A264971 If A262686(n) = 0, a(n) = 1, otherwise a(n) = 1 + a(A262686(n)), where A262686(n) = largest number k such that k - d(k) = n, or 0 if no such number exists, and d(n) = the number of divisors of n (A000005).

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

Offset

0,1

Comments

See comments at A264970.

Links

Antti Karttunen, Table of n, a(n) for n = 0..10000

Formula

If A060990(n) = 0, a(n) = 1, otherwise a(n) = 1 + a(A262686(n)).

Other identities. For all n >= 0:

a(n) = 1 + A264970(n).

Prog

(Scheme, with memoization-macro definec)
(definec (A264971 n) (cond ((A262686 n) => (lambda (lad) (if (zero? lad) 1 (+ 1 (A264971 lad)))))))

Crossrefs

Cf. A000005, A049820, A060990, A262686.

One more than A264970.

Number of significant terms on row n of A263271.

Sequence in context: A113172 A128154 A213538 * A107806 A138965 A317313

Adjacent sequences: A264968 A264969 A264970 * A264972 A264973 A264974

Keyword

nonn

Author

Antti Karttunen, Nov 29 2015

Status

approved