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.

A014318 Convolution of Catalan numbers and powers of 2.

Original entry on oeis.org

1, 3, 8, 21, 56, 154, 440, 1309, 4048, 12958, 42712, 144210, 496432, 1735764, 6145968, 21986781, 79331232, 288307254, 1054253208, 3875769606, 14315659632, 53097586284, 197677736208, 738415086066
Offset: 0

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Comments

Binomial transform of A097332: (1, 2, 3, 5, 9, 18, 39, ...). - Gary W. Adamson, Aug 01 2011
Hankel transform is A087960. - Wathek Chammam, Dec 02 2011

Crossrefs

Programs

  • Magma
    A014318:= func< n | (&+[2^(n-j)*Catalan(j): j in [0..n]]) >;
    [A014318(n): n in [0..40]]; // G. C. Greubel, Jan 09 2023
    
  • Maple
    a:=proc(n) options operator, arrow: sum(2^(n-j)*binomial(2*j,j)/(j+1), j=0..n) end proc: seq(a(n), n=0..23); # Emeric Deutsch, Oct 16 2008
  • Mathematica
    a[n_]:= a[n]= Sum[2^(n-j)*CatalanNumber[j], {j,0,n}];
    Table[a[n], {n,0,40}] (* G. C. Greubel, Jan 09 2023 *)
  • SageMath
    def A014318(n): return sum(2^(n-j)*catalan_number(j) for j in range(n+1))
    [A014318(n) for n in range(41)] # G. C. Greubel, Jan 09 2023

Formula

From Emeric Deutsch, Oct 16 2008: (Start)
G.f.: (1-sqrt(1-4*z))/(2*z*(1-2*z)).
a(n) = Sum_{j=0..n} (2^(n-j) * binomial(2*j,j)/(j+1)). (End)
a(n) = Sum_{j=0..n} abs(A106270(n, j)) * A000079(j). - Gary W. Adamson, Apr 02 2009
Recurrence: (n+1)*a(n) = 32*(2*n-7)*a(n-5) + 48*(8-3*n)*a(n-4) + 8*(16*n-29)*a(n-3) + 4*(13-14*n)*a(n-2) + 12*n*a(n-1), n>=5. - Fung Lam, Mar 09 2014
Asymptotics: a(n) ~ 2^(2n+1)/n^(3/2)/sqrt(Pi). - Fung Lam, Mar 21 2014
G.f. A(x) satisfies: A(x) = 1 / (1 - 2*x) + x * (1 - 2*x) * A(x)^2. - Ilya Gutkovskiy, Nov 21 2021