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.

A143464 Catalan transform of the Pell sequence.

Original entry on oeis.org

0, 1, 3, 11, 42, 164, 649, 2591, 10408, 41998, 170050, 690370, 2808714, 11446642, 46715469, 190876527, 780679200, 3195628806, 13090353594, 53655587034, 220045073988, 902842397664, 3705876933930, 15216954519222, 62503485455208
Offset: 0

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Author

Sergio Falcon, Oct 24 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:= a[n]= If[n==0, 0, Sum[i*Binomial[2n-i,n-i]*Fibonacci[i,2]/(2n-i), {i,n}]];
    Table[a[n], {n,0,30}] (* modified by G. C. Greubel, May 31 2022 *)
  • PARI
    my(x='x+O('x^66)); concat([0],Vec((1-5*x-(1+x)*sqrt(1-4*x))/(2*x^2+16*x-4))) \\ Joerg Arndt, May 01 2013
    
  • SageMath
    def Pell(n): return round( ((1+sqrt(2))^n - (1-sqrt(2))^n)/(2*sqrt(2)) )
    [0]+[(1/n)*sum(k*binomial(2*n-k-1, n-1)*Pell(k) for k in (1..n)) for n in (1..30)] # G. C. Greubel, May 31 2022

Formula

a(n) = Sum_{j=0..n} (j/(2*n-j))*binomial(2*n-j, n)*Pell(j), with a(0) = 0.
From Philippe Deléham, Oct 28 2008: (Start)
a(n) = Sum_{k=0..n} A106566(n,k)*A000129(k).
a(n) = Sum_{k=0..n} A039599(n,k)*A000035(k)*A016116(k). (End)
G.f.: ((1+x)*sqrt(1-4*x) - (1-5*x))/(2*(2 - 8*x - x^2)). - Mark van Hoeij, May 01 2013
a(n) = (1/(2*sqrt(2)))*Catalan(n-1)*Sum_{j=0..1} ((-1)^j + sqrt(2)) * Hypergeometric2F1([2,1-n], [2*(1-n)], 1+(-1)^j*sqrt(2)) - [n=0]/2. - G. C. Greubel, May 31 2022
a(n) ~ (1 + sqrt(2))^(2*n - 1) / 2^(2 + n/2). - Vaclav Kotesovec, May 31 2022

Extensions

Offset corrected by Philippe Deléham, Oct 28 2008