A261227 a(n) = number of steps to reach 0 when starting from k = n^3 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, 2, 5, 11, 20, 34, 53, 78, 109, 147, 191, 245, 307, 378, 459, 550, 653, 768, 897, 1039, 1196, 1368, 1555, 1758, 1979, 2217, 2473, 2747, 3041, 3354, 3689, 4046, 4424, 4824, 5248, 5697, 6170, 6669, 7194, 7746, 8325, 8934, 9571, 10237, 10935, 11664, 12424, 13216, 14043, 14903, 15798, 16727, 17694, 18696, 19735, 20812, 21929, 23084, 24279, 25514

Offset

0,3

Links

Antti Karttunen, Table of n, a(n) for n = 0..512

Formula

a(0) = 0, a(1) = 1; for n >= 2, a(n) = A261229(n-1) + a(n-1).

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

Prog

(Scheme, two variants, the first one using definec-macro)
(definec (A261227 n) (if (<= n 1) n (+ (A261229 (- n 1)) (A261227 (- n 1)))))
(define (A261227 n) (A261226 (* n n n)))

Crossrefs

Essentially one more than A261228.

First differences: A261229.

Cf. A000578, A055401, A261225, A261226.

Cf. also A261222.

Sequence in context: A093871 A139482 A038377 * A022908 A256310 A026390

Adjacent sequences: A261224 A261225 A261226 * A261228 A261229 A261230

Keyword

nonn

Author

Antti Karttunen, Aug 16 2015

Status

approved