A017958 Powers of sqrt(18) rounded down.

1, 4, 18, 76, 324, 1374, 5832, 24743, 104976, 445375, 1889568, 8016758, 34012224, 144301645, 612220032, 2597429617, 11019960576, 46753733110, 198359290368, 841567195983, 3570467226624, 15148209527700

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Examples

			sqrt(18)^2 = 18, so a(2) = 18.
sqrt(18)^3 = 76.3675323681471326352911911..., so a(3) = 76.
sqrt(18)^4 = 18^2 = 324, so a(4) = 324.
sqrt(18)^5 = 1374.61558262664838743524143993..., so a(5) = 1374.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..800

Crossrefs

Cf. A001027 (bisection)

Programs

Magma

[Floor(Sqrt(18^n)): n in [0..30]]; // Vincenzo Librandi, Jun 24 2011

Mathematica

Floor[Sqrt[18]^Range[0, 35]] (* Alonso del Arte, Dec 07 2017 *)

PARI

a(n)=sqrtint(18^n) \\ Charles R Greathouse IV, Nov 18 2011

Formula

a(n) = floor(sqrt(18^n)). - Vincenzo Librandi, Jun 24 2011