cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A130236 Partial sums of the 'upper' Fibonacci Inverse A130234.

Original entry on oeis.org

0, 1, 4, 8, 13, 18, 24, 30, 36, 43, 50, 57, 64, 71, 79, 87, 95, 103, 111, 119, 127, 135, 144, 153, 162, 171, 180, 189, 198, 207, 216, 225, 234, 243, 252, 262, 272, 282, 292, 302, 312, 322, 332, 342, 352, 362, 372, 382, 392, 402, 412, 422, 432, 442, 452, 462, 473
Offset: 0

Views

Author

Hieronymus Fischer, May 17 2007

Keywords

Crossrefs

Programs

  • Magma
    m:=120;
    f:= func< x | x*(&+[x^Fibonacci(j): j in [0..Floor(3*Log(3*m+1))]])/(1-x)^2 >;
    R:=PowerSeriesRing(Rationals(), m+1);
    [0] cat Coefficients(R!( f(x) )); // G. C. Greubel, Mar 18 2023
    
  • Mathematica
    b[n_]:= For[i=0, True, i++, If[Fibonacci[i] >= n, Return[i]]];
    b/@ Range[0, 56]//Accumulate (* Jean-François Alcover, Apr 13 2020 *)
  • SageMath
    m=120
    def f(x): return x*sum( x^fibonacci(j) for j in range(1+int(3*log(3*m+1))))/(1-x)^2
    def A130236_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( f(x) ).list()
    A130236_list(m) # G. C. Greubel, Mar 18 2023

Formula

a(n) = Sum_{k=0..n} A130234(k).
a(n) = n*A130234(n) - Fibonacci(A130234(n)+1) + 1.
G.f.: (x/(1-x)^2) * Sum_{k>=0} x^Fibonacci(k).

A130257 Partial sums of the 'lower' odd Fibonacci Inverse A130255.

Original entry on oeis.org

1, 3, 5, 7, 10, 13, 16, 19, 22, 25, 28, 31, 35, 39, 43, 47, 51, 55, 59, 63, 67, 71, 75, 79, 83, 87, 91, 95, 99, 103, 107, 111, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250
Offset: 1

Views

Author

Hieronymus Fischer, May 24 2007

Keywords

Crossrefs

Programs

  • Magma
    [(&+[Floor((1+Argsinh(Sqrt(5)*k/2)/Log((1+Sqrt(5))/2))/2): k in [1..n]]): n in [1..100]]; // G. C. Greubel, Sep 09 2018
  • Mathematica
    Table[Sum[Floor[(1 + ArcSinh[Sqrt[5]*k/2]/Log[GoldenRatio])/2], {k, 1, n}], {n, 1, 100}] (* G. C. Greubel, Sep 09 2018 *)
  • PARI
    for(n=1,100, print1(sum(k=1,n, floor((1+asinh(sqrt(5)*k/2)/log((1+sqrt(5))/2))/2)), ", ")) \\ G. C. Greubel, Sep 09 2018
    

Formula

a(n) = (n+1)*A130255(n) - A001906(A130255(n)).
a(n) = (n+1)*A130255(n) - Fib(2*A130255(n)).
G.f.: g(x)=1/(1-x)^2*sum(k>=1, x^Fib(2k-1)).

A130244 Partial sums of the 'upper' Lucas Inverse A130242.

Original entry on oeis.org

0, 0, 0, 2, 5, 9, 13, 17, 22, 27, 32, 37, 43, 49, 55, 61, 67, 73, 79, 86, 93, 100, 107, 114, 121, 128, 135, 142, 149, 156, 164, 172, 180, 188, 196, 204, 212, 220, 228, 236, 244, 252, 260, 268, 276, 284, 292, 300, 309, 318, 327, 336, 345, 354, 363, 372, 381, 390
Offset: 0

Views

Author

Hieronymus Fischer, May 19 2007

Keywords

Crossrefs

Other related sequences: A000032, A130241, A130243, A130245, A130246, A130248, A130252, A130258, A130262. Fibonacci inverse see A130233 - A130240, A104162.

Programs

  • Magma
    [0,0] cat [(&+[Ceiling(Log(k + 1/2)/Log((1+Sqrt(5))/2)) : k in [0..n]]): n in [1..50]]; // G. C. Greubel, Sep 12 2018
  • Mathematica
    Join[{0, 0}, Table[Sum[Ceiling[Log[GoldenRatio, k + 1/2]], {k, 0, n}], {n, 1, 50}]] (* G. C. Greubel, Sep 12 2018 *)
  • PARI
    for(n=-1,50, print1(if(n==-1, 0, if(n==0, 0, sum(k=0, n, ceil(log(k + 1/2)/log((1+sqrt(5))/2))))), ", ")) \\ G. C. Greubel, Sep 12 2018
    

Formula

a(n) = Sum_{k=0..n} A130242(k).
a(n) = n*A130242(n) - A000032(A130242(n) +1) for n>=3.
G.f.: x/(1-x)^2*(2*x^2 + Sum{k>=2, x^Lucas(k)}).

A130256 Minimal index k of an odd Fibonacci number A001519 such that A001519(k) = Fibonacci(2*k-1) >= n (the 'upper' odd Fibonacci Inverse).

Original entry on oeis.org

0, 0, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
Offset: 0

Views

Author

Hieronymus Fischer, May 24 2007, Jul 02 2007

Keywords

Comments

Inverse of the odd Fibonacci sequence (A001519), nearly, since a(A001519(n))=n except for n=1 (see A130255 for another version).
a(n+1) is the number of odd Fibonacci numbers (A001519) <= n (for n >= 0).

Examples

			a(10)=4 because A001519(4) = 13 >= 10, but A001519(3) = 5 < 10.
		

Crossrefs

Cf. partial sums A130258.
Other related sequences: A000045, A001906, A130234, A130237, A130239, A130255, A130260.
Lucas inverse: A130241 - A130248.

Programs

  • Magma
    [0,0] cat [Ceiling((1/2)*(1 + Log(Sqrt(5)*n-1)/(Log((1+Sqrt(5))/2)))): n in [2..100]]; // G. C. Greubel, Sep 12 2018
  • Mathematica
    Join[{0, 0}, Table[Ceiling[1/2*(1 + Log[GoldenRatio, (Sqrt[5]*n - 1)])], {n, 2, 100}]] (* G. C. Greubel, Sep 12 2018 *)
  • PARI
    for(n=0,100, print1(if(n==0, 0, if(n==1, 0, ceil((1/2)*(1 + log(sqrt(5)*n-1)/(log((1+sqrt(5))/2)))))), ", ")) \\ G. C. Greubel, Sep 12 2018
    

Formula

a(n) = ceiling((1+arccosh(sqrt(5)*n/2)/log(phi))/2), where phi=(1+sqrt(5))/2.
G.f.: (x/(1-x))*Sum_{k>=0} x^Fibonacci(2*k-1).
a(n) = ceiling((1/2)*(1+log_phi(sqrt(5)*n-1))) for n >= 2, where phi=(1+sqrt(5))/2.
Showing 1-4 of 4 results.