A129957 a(n) = n^3 if n is odd, n^3 + 1 otherwise.

1, 1, 9, 27, 65, 125, 217, 343, 513, 729, 1001, 1331, 1729, 2197, 2745, 3375, 4097, 4913, 5833, 6859, 8001, 9261, 10649, 12167, 13825, 15625, 17577, 19683, 21953, 24389, 27001, 29791, 32769, 35937, 39305, 42875, 46657, 50653, 54873, 59319

Offset

0,3

Comments

Suggested by a problem in stacking tetrahedra and cubes.

Links

Table of n, a(n) for n=0..39.

Index entries for linear recurrences with constant coefficients, signature (3,-2,-2,3,-1).

Formula

G.f.: (1-2*x+8*x^2+4*x^3+x^4)/((1-x)^4*(1+x)). [Colin Barker, May 09 2012]

Mathematica

f[n_] := If[Mod[n, 2] == 0, n^3 + 1, n^3]; Table[f[n], {n, 0, 30}]

Crossrefs

Sequence in context: A029875 A335671 A337628 * A373479 A328408 A198956

Adjacent sequences: A129954 A129955 A129956 * A129958 A129959 A129960

Keyword

nonn,easy

Author

Roger L. Bagula, Jun 10 2007

Extensions

Edited, corrected and extended by Stefan Steinerberger, Jul 21 2007

Status

approved