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.

A109262 A Catalan transform of the Fibonacci numbers.

Original entry on oeis.org

0, 1, 2, 6, 19, 63, 215, 749, 2650, 9490, 34318, 125104, 459152, 1694914, 6287896, 23429158, 87635243, 328917615, 1238303243, 4674847097, 17692789741, 67114622451, 255120892105, 971649360211, 3707176155659, 14167390221873
Offset: 0

Views

Author

Paul Barry, Jun 24 2005

Keywords

Comments

A column of A109267.
Hankel transform is -Fibonacci(2*n). a(n+1) has Hankel transform Fibonacci(2*n+1). - Paul Barry, Nov 22 2007

Crossrefs

Programs

  • Magma
    [n eq 0 select 0 else (&+[k*Binomial(2*n-k-1,n-1)*Fibonacci(k): k in [0..n]])/n: n in [0..30]]; // G. C. Greubel, May 30 2022
    
  • Mathematica
    CoefficientList[Series[(1-Sqrt[1-4*x])/(2*(Sqrt[1-4*x]+x)), {x, 0, 20}], x] (* Vaclav Kotesovec, Feb 13 2014 *)
  • SageMath
    [0]+[(1/n)*sum(k*binomial(2*n-k-1, n-1)*fibonacci(k) for k in (1..n)) for n in (1..30)] # G. C. Greubel, May 30 2022

Formula

G.f.: x*c(x)/(1 - x*c(x) - x^2*c(x)^2) = (1 - sqrt(1-4*x))/(2*(x + sqrt(1-4*x))) where c(x) is the g.f. of A000108.
a(n) = Sum_{k=0..n} (k/(2*n-k))*binomial(2*n-k, n-k)*Fibonacci(k).
a(n) = Sum_{k=0..n} A106566(n,k)*A000045(k). - Philippe Deléham, Oct 28 2008
a(n) = Sum_{k=0..n} A039599(n,k)*(-1)^(k+1)*A000045(k). - Philippe Deléham, Oct 28 2008
n*a(n) - (7*n-4)*a(n-1) + (7*n-2)*a(n-2) + (19*n-60)*a(n-3) + 2*(2*n-7)*a(n-4) = 0. - R. J. Mathar, Nov 26 2012
Recurrence: n*(5*n-11)*a(n) = 2*(20*n^2 - 59*n + 30)*a(n-1) - 15*(5*n^2 - 19*n + 16)*a(n-2) - 2*(2*n-5)*(5*n-6)*a(n-3). - Vaclav Kotesovec, Feb 13 2014
a(n) ~ 5*4^n/(sqrt(Pi)*n^(3/2)). - Vaclav Kotesovec, Feb 13 2014
a(n) = (1/(2*sqrt(5)))*Catalan(n-1)*Sum_{j=0..1} ((-1)^j + sqrt(5)) * Hypergeometric2F1([2,1-n], [2*(1-n)], (1+(-1)^j*sqrt(5))/2). - G. C. Greubel, May 30 2022

A109263 A Catalan transform of F(n-1)-0^n.

Original entry on oeis.org

0, 0, 1, 3, 10, 34, 118, 416, 1485, 5355, 19473, 71313, 262735, 973027, 3619955, 13521307, 50684778, 190597594, 718788034, 2717755820, 10300186824, 39121645886, 148884623768, 567643844338, 2167882951110, 8292331115104
Offset: 0

Views

Author

Paul Barry, Jun 24 2005

Keywords

Comments

A column of A109267.
Define a triangle by T(n,0)=A000045(n) and T(n,k)=sum_{r=k-1..n} T(r,k-1). (The column k=1 is A000071, the column k=2 is A001924 etc). Then T(n,n)=a(n+1). - J. M. Bergot, May 22 2013

Formula

G.f.: x^2c(x)^2/(1-xc(x)-x^2c(x)^2) where c(x) is the g.f. of A000108; a(n)=sum{k=0..n, (k/(2n-k))binomial(2n-k, n-k)(F(k-1)-0^k)}.
Conjecture: n*(n-3)*a(n) +2*(-4*n^2+15*n-10)*a(n-1) +(15*n^2-69*n+80)*a(n-2) +2*(n-2)*(2*n-5)*a(n-3)=0. - R. J. Mathar, Nov 09 2012

A109264 Riordan array (1-x-x^2,x(1-x)).

Original entry on oeis.org

1, -1, 1, -1, -2, 1, 0, 0, -3, 1, 0, 1, 2, -4, 1, 0, 0, 1, 5, -5, 1, 0, 0, -1, -1, 9, -6, 1, 0, 0, 0, -2, -6, 14, -7, 1, 0, 0, 0, 1, -1, -15, 20, -8, 1, 0, 0, 0, 0, 3, 5, -29, 27, -9, 1, 0, 0, 0, 0, -1, 4, 20, -49, 35, -10, 1, 0, 0, 0, 0, 0, -4, -1, 49, -76, 44, -11, 1, 0, 0, 0, 0, 0, 1, -8, -21, 98, -111, 54, -12, 1
Offset: 0

Views

Author

Paul Barry, Jun 24 2005

Keywords

Comments

Rows sums are A109265. Diagonal sums are A109266. Inverse is A109267.

Examples

			Rows begin
1;
-1,1;
-1,-2,1;
0,0,-3,1;
0,1,2,-4,1;
0,0,1,5,-5,1;
0,0,-1,-1,9,-6,1;
		

A109268 Expansion of 1/((1-xc(x)-x^2c(x)^2)(1-x^2c(x))) with c(x) the g.f. of A000108.

Original entry on oeis.org

1, 1, 4, 11, 36, 119, 407, 1418, 5018, 17971, 64989, 236915, 869518, 3209735, 11907644, 44368636, 165957615, 622880402, 2345005449, 8852862717, 33505203060, 127096279124, 483127286394, 1840030664115, 7020349647422
Offset: 0

Views

Author

Paul Barry, Jun 24 2005

Keywords

Comments

Diagonal sums of A109267.

Formula

G.f.: (2-x-x*sqrt(1-4x))(sqrt(1-4x)-x)/(2(1-4x-x^2)(1-x+x^3))
Showing 1-4 of 4 results.