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.

A188108 Triangle T(n,m) read by rows, obtained from [A(x)]^m = Sum_{n>=m} T(n,m)*x^n, where A(x) (the g.f. for A069271) satisfies 2*x^2*A(x)^3 = 1 - 2*x*A(x) - sqrt(1-4*x*A(x)).

Original entry on oeis.org

1, 2, 1, 9, 4, 1, 52, 22, 6, 1, 340, 140, 39, 8, 1, 2394, 969, 272, 60, 10, 1, 17710, 7084, 1995, 456, 85, 12, 1, 135720, 53820, 15180, 3542, 700, 114, 14, 1, 1068012, 420732, 118755, 28080, 5750, 1012, 147, 16, 1, 8579560, 3362260, 949344, 226548, 47502, 8775, 1400, 184, 18, 1, 70068713, 27343888, 7721604, 1855040, 395560, 75516, 12789, 1872, 225, 20, 1, 580034052, 225568798, 63698830, 15380937, 3321120, 649264, 114576, 17980, 2436, 270, 22, 1
Offset: 1

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Author

Vladimir Kruchinin, Mar 20 2011

Keywords

Comments

T(n,1)/n is A000260(n). - Vladimir Kruchinin, Apr 02 2015

Examples

			1;
2, 1;
9, 4, 1;
52, 22, 6, 1;
340, 140, 39, 8, 1;
2394, 969, 272, 60, 10, 1;
17710, 7084, 1995, 456, 85, 12,...
A(x)=x+2*x^2+9*x^3+52*x^4+340*x^5+2394*x^6+17710*x^7+135720*x^8+1068012*x^9+8579560*x^10
taylor(1/(1-A(x)*y)-1,x,0,7,y,0,7);
(y)*x+
(2*y+y^2)*x^2+
(9*y+4*y^2+y^3)*x^3+
(52*y+22*y^2+6*y^3+y^4)*x^4+
(340*y+140*y^2+39*y^3+8*y^4+y^5)*x^5
(2394*y+969*y^2+272*y^3+60*y^4+10*y^5+y^6)*x^6+
(17710*y+7084*y^2+1995*y^3+456*y^4+85*y^5+12*y^6+y^7)*x^7+
...
		

Crossrefs

Programs

  • Maxima
    T(n,m):=if n=m then 1 else sum((2*m*binomial(2*m+2*k-1,k))/(2*m+k)*T(n-m,k),k,1,n-m); /* Vladimir Kruchinin, Apr 02 2015 */
    T(n,k):=if n<0 or k<0 or nVladimir Kruchinin, May 02 2015 */

Formula

T(n,m) = Sum_{i=1..n-m+1} A069271(i)*T(n-i,m-1), m>0, T(n,1) = A069271(n-1).
T(n,m) = (m/n)*A039598(2*n-m-1,n-1).
T(n,m) = Sum_{k=1..n-m} ((2*m*binomial(2*m+2*k-1,k))/(2*m+k)*T(n-m,k)), T(n,n)=1. - Vladimir Kruchinin, Apr 02 2015
G.f.: 1/(1-x*y*A(x))-1, where A(x) is g.f. for A069271. - Vladimir Kruchinin, May 03 2015