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.

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A362713 Expansion of e.g.f. x*2F1([3/4, 3/4], [3/2], 4*x^2)/2F1([1/4, 1/4], [1/2], 4*x^2), odd powers only.

Original entry on oeis.org

1, 6, 256, 28560, 6071040, 2098483200, 1071889920000, 758870167910400, 711206089850880000, 852336059876720640000, 1271438437097485762560000, 2310211006286602237378560000, 5023141810386294125321256960000, 12877606625796048169971744768000000, 38439740210093310755176533983232000000
Offset: 0

Views

Author

Stefano Spezia, Apr 30 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(2n+1)!SeriesCoefficient[x*Hypergeometric2F1[3/4, 3/4, 3/2, 4*x^2]/Hypergeometric2F1[1/4, 1/4, 1/2, 4*x^2], {x, 0, 2n+1}], {n,0, 14}]
    (* or *)
    a[0]=1; a[n_]:=Product[(4j-1)^2,{j,n}]-Sum[Binomial[2n+1,2m+1]Product[(4j-3)^2,{j,n-m}]a[m],{m,0,n-1}]; Array[a,15,0]

Formula

a(n) = Product_{j=1..n} (4*j - 1)^2 - Sum_{m=0..n-1} binomial(2*n+1, 2*m+1)*Product_{j=1..n-m} (4*j - 3)^2*a(m) for n > 0.

A362715 Triangle read by rows: T(n, k) = 2^(n-k)*(2*n)!/(2*k)! * [x^(2*n)] U[x]^(2*k), where U(x) = x*2F1([3/4, 3/4], [3/2], 4*x^2)/2F1([1/4, 1/4], [1/2], 4*x^2).

Original entry on oeis.org

1, 0, 1, 0, 48, 1, 0, 7584, 240, 1, 0, 2515968, 97664, 672, 1, 0, 1432498176, 63221760, 560448, 1440, 1, 0, 1247557386240, 60299053056, 628024320, 2141568, 2640, 1, 0, 1542446268088320, 79885647249408, 933093697536, 3819239424, 6374368, 4368, 1
Offset: 0

Views

Author

Stefano Spezia, Apr 30 2023

Keywords

Examples

			The triangle begins:
    1;
    0,          1;
    0,         48,        1;
    0,       7584,      240,      1;
    0,    2515968,    97664,    672,    1;
    0, 1432498176, 63221760, 560448, 1440, 1;
    ...
		

Crossrefs

Programs

  • Mathematica
    U[x_]:=x*Hypergeometric2F1[3/4, 3/4, 3/2, 4*x^2]/Hypergeometric2F1[1/4, 1/4, 1/2, 4*x^2]; T[n_,k_]:=2^(n-k)(2n)!/(2k)!SeriesCoefficient[U[x]^(2k),{x,0,2n}]; Table[T[n,k],{n,0,7},{k,0,n}]//Flatten
Showing 1-2 of 2 results.