A061287 Integer part of square root of n-th Fibonacci number.

0, 1, 1, 1, 1, 2, 2, 3, 4, 5, 7, 9, 12, 15, 19, 24, 31, 39, 50, 64, 82, 104, 133, 169, 215, 273, 348, 443, 563, 717, 912, 1160, 1475, 1877, 2388, 3037, 3863, 4915, 6252, 7952, 10116, 12867, 16368, 20820, 26484, 33688, 42852, 54508, 69336, 88197, 112188

Offset: 0

Author

Amarnath Murthy, Apr 25 2001

Keywords

• nonn
• easy

Examples

			a(10) = 7 because the 10th Fibonacci number is 55 and floor(sqrt(55)) = floor(7.4161) = 7.
		

Links

• Harry J. Smith, Table of n, a(n) for n = 0..500

Programs

Magma

[Floor(Sqrt(Fibonacci(n))): n in [0..50]]; // Vincenzo Librandi, Sep 29 2017

Mathematica

Array[Floor[Sqrt[Fibonacci[ # ]]]&,5!,0] (* Vladimir Joseph Stephan Orlovsky, Nov 10 2009 *)

Maxima

makelist(floor(sqrt(fib(n))),n,0,24); /* Emanuele Munarini, Jul 07 2011 */

PARI

{ g=0; f=1; for (n=0, 500, write("b061287.txt", n, " ", sqrtint(g)); s=f; f+=g; g=s ) } \\ Harry J. Smith, Jul 20 2009

Sage

[floor(sqrt(fibonacci(n))) for n in range(0,51)] # Zerinvary Lajos, Dec 01 2009

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001