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.

A124460 Rectangular table, read by antidiagonals, such that the o.g.f. of row n, R_n(y), satisfies: R_n(y) = Sum_{k>=0} y^k * R_k(y)^n for n>=0, with R_0(y) = 1/(1-y).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 4, 1, 1, 4, 8, 9, 1, 1, 5, 13, 23, 23, 1, 1, 6, 19, 44, 73, 66, 1, 1, 7, 26, 73, 162, 251, 210, 1, 1, 8, 34, 111, 302, 637, 919, 731, 1, 1, 9, 43, 159, 506, 1325, 2622, 3549, 2744, 1, 1, 10, 53, 218, 788, 2437, 6032, 11188, 14371, 10959, 1, 1, 11, 64, 289
Offset: 0

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Author

Paul D. Hanna, Nov 03 2006

Keywords

Comments

Antidiagonal sums forms row 1.

Examples

			Row o.g.f.s R_n(y) satisfy:
R_n(y) = R_0(y)^n + y*R_1(y)^n + y^2*R_2(y)^n + y^3*R_3(y)^n +...
more explicitly:
R_0 = 1 + y + y^2 + y^3 + y^4 + ...
R_1 = (R_0) + y*(R_1) + y^2*(R_2) + y^3*(R_3) + y^4*(R_4) + ...
R_2 = (R_0)^2 + y*(R_1)^2 + y^2*(R_2)^2 + y^3*(R_3)^2 + y^4*(R_4)^2 +...
R_3 = (R_0)^3 + y*(R_1)^3 + y^2*(R_2)^3 + y^3*(R_3)^3 + y^4*(R_4)^3 +...
R_4 = (R_0)^4 + y*(R_1)^4 + y^2*(R_2)^4 + y^3*(R_3)^4 + y^4*(R_4)^4 +...
etc., for all rows.
Rectangular table begins:
1,1,1,1,1,1,1,1,1,1,1,1,...
1,2,4,9,23,66,210,731,2744,10959,46058,202028,...
1,3,8,23,73,251,919,3549,14371,60720,266481,1209807,...
1,4,13,44,162,637,2622,11188,49293,223768,1044661,5006126,...
1,5,19,73,302,1325,6032,28193,134825,659011,3290110,16764206,...
1,6,26,111,506,2437,12118,61499,317485,1666371,8891543,48221602,...
1,7,34,159,788,4117,22143,121079,670811,3764758,21408813,123367344,...
1,8,43,218,1163,6532,37703,220663,1304831,7795435,47075775,287431878,...
1,9,53,289,1647,9873,60767,378529,2377322,15055045,96196848,620412879,..
1,10,64,373,2257,14356,93718,618367,4106995,27462836,185031258,...
1,11,76,471,3011,20223,139395,970217,6788744,47766886,338270681,...
1,12,89,584,3928,27743,201136,1471482,10811098,79794397,592228264,...
		

Crossrefs

Rows: A124461, A124462, A124463, A124464, A124465, A124466; diagonals: A124467, A124468; related table: A124469.

Programs

  • PARI
    {T(n,k)=local(m=max(n,k),R=vector(m+1,r,vector(m+1,c,binomial(r+c-2,c-1)))); for(i=0,m,for(r=0,m,R[r+1]=Vec(sum(c=0,m,x^c*Ser(R[c+1])^r+O(x^(m+1))))));R[n+1][k+1]}

Formula

O.g.f.: A(x,y) = Sum_{n>=0} x^n*R_n(y) = Sum_{k>=0} y^k/(1 - x*R_k(y)) ; E.g.f.: A(x,y) = Sum_{n>=0} x^n*R_n(y)/n! = Sum_{k>=0} y^k*exp(x*R_k(y)) where R_n(y) is the o.g.f. of row n.