A018036 Powers of cube root of 21 rounded down.

1, 2, 7, 21, 57, 159, 441, 1216, 3356, 9261, 25550, 70491, 194481, 536558, 1480323, 4084101, 11267724, 31086798, 85766121, 236622224, 652822776, 1801088541, 4969066719, 13709278306, 37822859361, 104350401110, 287894844440, 794280046581, 2191358423329

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• changed

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200

Crossrefs

Cf. powers of cube root of k rounded down: A017979 (k=2), A017982 (k=3), A017985 (k=4), A017988 (k=5), A017991 (k=6), A017994 (k=7), A018000 (k=9), A018003 (k=10), A018006 (k=11), A018009 (k=12), A018012 (k=13), A018015 (k=14), A018018 (k=15), A018021 (k=16), A018024 (k=17), A018027 (k=18), A018030 (k=19), A018033 (k=20), this sequence (k=21), A018039 (k=22), A018042 (k=23), A018045 (k=24).

Programs

Magma

[Floor(21^(n/3)): n in [0..40]]; // Vincenzo Librandi, Jan 06 2014

Mathematica

Table[Floor[21^(n/3)], {n, 0, 40}]  (* Vincenzo Librandi, Jan 06 2014 *)
Floor[CubeRoot[21]^Range[0,30]] (* Harvey P. Dale, May 25 2025 *)

Formula

a(n) = floor(21^(n/3)). - Wesley Ivan Hurt, Sep 05 2025

Extensions

More terms from Vincenzo Librandi, Jan 06 2014