A261228 a(n) = number of steps to reach 0 when starting from k = (n^3)-1 and repeatedly applying the map that replaces k with k - A055401(k), where A055401(k) = the number of positive cubes needed to sum to k using the greedy algorithm.

0, 1, 4, 10, 19, 33, 52, 77, 108, 146, 190, 244, 306, 377, 458, 549, 652, 767, 896, 1038, 1195, 1367, 1554, 1757, 1978, 2216, 2472, 2746, 3040, 3353, 3688, 4045, 4423, 4823, 5247, 5696, 6169, 6668, 7193, 7745, 8324, 8933, 9570, 10236, 10934, 11663, 12423, 13215, 14042, 14902, 15797, 16726, 17693, 18695, 19734, 20811, 21928, 23083, 24278, 25513

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..512

Formula

a(1) = 0; for n > 1, a(n) = A261229(n-1) + a(n-1).

a(n) = A261226((n^3)-1).

Prog

(Scheme, two variants, the first one using definec-macro)
(definec (A261228 n) (if (= 1 n) 0 (+ (A261229 (- n 1)) (A261228 (- n 1)))))
(define (A261228 n) (A261226 (- (* n n n) 1)))

Crossrefs

One less than A261227.

First differences: A261229.

Cf. A000578, A055401, A261225, A261226.

Cf. also A261223.

Sequence in context: A102534 A093111 A009857 * A173154 A008126 A301129

Adjacent sequences: A261225 A261226 A261227 * A261229 A261230 A261231

Keyword

nonn

Author

Antti Karttunen, Aug 16 2015

Status

approved