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Square excess of Fibonacci numbers.
3

%I #21 Oct 26 2022 20:07:52

%S 0,0,0,1,2,1,4,4,5,9,6,8,0,8,16,34,26,76,84,85,41,130,22,96,143,496,

%T 289,169,842,140,296,669,2684,1449,343,4096,7583,592,665,11682,699,

%U 20452,2872,22037,6477,21826,17999,93009,46080,31240,121681,8638,317523

%N Square excess of Fibonacci numbers.

%H G. C. Greubel, <a href="/A190993/b190993.txt">Table of n, a(n) for n = 0..5000</a>

%p a:= n-> (f-> f-floor(sqrt(f))^2)((<<0|1>, <1|1>>^n)[1, 2]):

%p seq(a(n), n=0..52); # _Alois P. Heinz_, Oct 26 2022

%t A000045=Fibonacci[Range[0,100]]; Table[A000045[[n]]-Floor[Sqrt[A000045[[n]]]]^2,{n,Length[A000045]}]

%o (PARI) a(n) = my(f=fibonacci(n)); f - sqrtint(f)^2; \\ _Michel Marcus_, Nov 11 2015

%o (Magma) [Fibonacci(n) - Floor(Sqrt(Fibonacci(n)))^2: n in [0..100]]; // _G. C. Greubel_, Oct 26 2022

%o (SageMath) [fibonacci(n) - isqrt(fibonacci(n))^2 for n in range(101)] # _G. C. Greubel_, Oct 26 2022

%Y Cf. A000045, A190992, A216223.

%K nonn

%O 0,5

%A _Vladimir Joseph Stephan Orlovsky_, Jun 02 2011

%E a(0) prepended by _Alois P. Heinz_, Nov 11 2015