A017966 Powers of sqrt(20) rounded up.

1, 5, 20, 90, 400, 1789, 8000, 35778, 160000, 715542, 3200000, 14310836, 64000000, 286216702, 1280000000, 5724334023, 25600000000, 114486680448, 512000000000, 2289733608960, 10240000000000, 45794672179196

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..700

Mathematica

Ceiling[(Sqrt[20])^Range[0, 40]] (* Vincenzo Librandi, Nov 21 2011 *)

Prog

(Magma) [Ceiling(Sqrt(20^n)): n in [0..30]]; // Vincenzo Librandi, Nov 21 2011

Crossrefs

Sequence in context: A271096 A269716 A192249 * A360076 A365115 A375455

Adjacent sequences: A017963 A017964 A017965 * A017967 A017968 A017969

Keyword

nonn

Author

N. J. A. Sloane

Status

approved