A263259 a(n) = number of integers k <= n for which A155043(k) = A155043(n).

1, 1, 2, 1, 2, 1, 3, 1, 2, 3, 4, 2, 5, 1, 3, 2, 3, 1, 4, 1, 4, 2, 5, 1, 2, 3, 4, 1, 5, 1, 6, 1, 3, 2, 4, 1, 2, 1, 2, 2, 3, 1, 4, 1, 2, 2, 3, 2, 4, 3, 4, 1, 5, 1, 6, 2, 7, 1, 3, 1, 8, 1, 2, 2, 3, 1, 3, 1, 3, 2, 4, 1, 4, 1, 3, 2, 4, 1, 5, 1, 6, 3, 4, 2, 4, 3, 4, 3, 5, 2, 6, 3, 4, 4, 5, 5, 5, 2, 4, 3, 6, 2, 5, 3, 7, 3, 5, 4, 8, 3, 6, 4, 7, 2, 7, 3, 8, 4, 4, 2, 7

Offset

0,3

Comments

a(n) = one-based index of n in row A155043(n) of table A263265.

Links

Antti Karttunen, Table of n, a(n) for n = 0..12333

Formula

Other identities. For all n >= 0:

a(A261089(n)) = 1.

a(A262503(n)) = A262507(n).

A263265(A155043(n), a(n)) = n.

Prog

(Scheme, with memoizing definec-macro)
(definec (A263259 n) (cond ((zero? n) 1) ((= 1 (- (A263089 n) (A263089 (- n 1)))) 1) (else (let ((d (A155043 n))) (let loop ((k (- n 1))) (if (= (A155043 k) d) (+ 1 (A263259 k)) (loop (- k 1))))))))

Crossrefs

Cf. A000005, A155043, A261089, A262503, A262507, A263089, A263265, A263279.

Sequence in context: A077767 A355319 A322317 * A137163 A344233 A072625

Adjacent sequences: A263256 A263257 A263258 * A263260 A263261 A263262

Keyword

nonn

Author

Antti Karttunen, Nov 24 2015

Status

approved