A018105 Powers of fourth root of 21 rounded down.

1, 2, 4, 9, 21, 44, 96, 206, 441, 944, 2020, 4326, 9261, 19824, 42439, 90849, 194481, 416324, 891223, 1907838, 4084101, 8742815, 18715701, 40064612, 85766121, 183599118, 393029741, 841356858, 1801088541, 3855581491, 8253624572, 17668494033, 37822859361

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Formula

a(n) = floor((21)^(n/4)). - Wesley Ivan Hurt, Apr 24 2017

Maple

A018105:=n->floor((21)^(n/4)): seq(A018105(n), n=0..40); # Wesley Ivan Hurt, Apr 24 2017

Mathematica

Table[Floor[21^(n/4)], {n, 0, 30}] (* Vincenzo Librandi, Apr 25 2017 *)

Prog

(Magma) [Floor(21^(n/4)) : n in [0..40]]; // Vincenzo Librandi, Apr 25 2017

Crossrefs

Cf. A011017 (fourth root of 21).

Sequence in context: A225173 A346737 A030039 * A035056 A332800 A093698

Adjacent sequences: A018102 A018103 A018104 * A018106 A018107 A018108

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved