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.

A262014 Triangle in which the g.f. for row n is (1-x)^(4*n+1) * Sum_{j>=0} binomial(n+j-1,j)^4 * x^j, read by rows of k=0..3*n terms.

Original entry on oeis.org

1, 1, 11, 11, 1, 1, 72, 603, 1168, 603, 72, 1, 1, 243, 6750, 49682, 128124, 128124, 49682, 6750, 243, 1, 1, 608, 40136, 724320, 4961755, 15018688, 21571984, 15018688, 4961755, 724320, 40136, 608, 1, 1, 1275, 167475, 6021225, 84646275, 554083761, 1858142825, 3363309675, 3363309675, 1858142825, 554083761, 84646275, 6021225, 167475, 1275, 1, 1, 2376, 554931, 35138736, 879018750, 10490842656, 66555527346, 239677178256, 509723668476, 654019630000, 509723668476
Offset: 0

Views

Author

Paul D. Hanna, Sep 10 2015

Keywords

Examples

			Triangle begins:
 1;
 1, 11, 11, 1;
 1, 72, 603, 1168, 603, 72, 1;
 1, 243, 6750, 49682, 128124, 128124, 49682, 6750, 243, 1;
 1, 608, 40136, 724320, 4961755, 15018688, 21571984, 15018688, 4961755, 724320, 40136, 608, 1;
 1, 1275, 167475, 6021225, 84646275, 554083761, 1858142825, 3363309675, 3363309675, 1858142825, 554083761, 84646275, 6021225, 167475, 1275, 1;
 1, 2376, 554931, 35138736, 879018750, 10490842656, 66555527346, 239677178256, 509723668476, 654019630000, 509723668476, 239677178256, 66555527346, 10490842656, 879018750, 35138736, 554931, 2376, 1;
 ...
Row g.f.s begin:
 n=0: (1) = (1-x) * (1 + x + x^2 + x^3 + x^4 +...);
 n=1: (1 + 11*x + 11*x^2 + x^3)  =  (1-x)^5 * (1 + 2^4*x + 3^4*x^2 + 4^4*x^3 + 5^4*x^4 + 6^4*x^5 +...);
 n=2: (1 + 72*x + 603*x^2 + 1168*x^3 + 603*x^4 + 72*x^5 + x^6)  =  (1-x)^9 * (1 + 3^4*x + 6^4*x^2 + 10^4*x^3 + 15^4*x^5 + 21^4*x^6 +...);
 n=3: (1 + 243*x + 6750*x^2 + 49682*x^3 + 128124*x^4 + 128124*x^5 + 49682*x^6 + 6750*x^7 + 243*x^8 + x^9)  =  (1-x)^13 * (1 + 4^4*x + 10^4*x^2 + 20^4*x^3 + 35^4*x^4 + 56^4*x^5 + 84^4*x^6 +...);
 ...
		

Crossrefs

Cf. A008977 (row sums), A262015 (diagonal), A202750, A258402.
Cf. A181544 (triangle variant).

Programs

  • PARI
    {T(n, k)=polcoeff(sum(j=0, n+k, binomial(n+j, j)^4*x^j)*(1-x)^(4*n+1), k)}
    for(n=0, 10, for(k=0, 3*n, print1(T(n, k), ", ")); print(""))

Formula

Row sums form A008977(n) = (4*n)!/(n!)^4.
T(n,1) = A258402(n) = (n^2 + 4*n + 6) * n^2.
From Sergii Voloshyn, Dec 17 2024: (Start)
Let E be the operator D*x*D*x*D*x*D, where D denotes the derivative operator d/dx. Then (1/(n)!^4) * E^n(1/(1 - x)) = (row n generating polynomial)/(1 - x)^(4*n+1) = Sum_{j>=0} binomial(n+j,j)^4 * x^j.
For example, when n = 2 we have (1/2!)^4*E^3(1/(1 - x)) = (1 + 243 x + 6750 x^2 + 49682 x^3 + 128124 x^4 + 128124 x^5 + 49682 x^6 + 6750 x^7 + 243 x^8 + x^9)/(1 - x)^13. (End)