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.

A366230 Expansion of e.g.f. A(x,y) satisfying A(x,y) = 1 + x*A(x,y) * exp(x*y * A(x,y)), as a triangle read by rows.

Original entry on oeis.org

1, 1, 0, 2, 2, 0, 6, 18, 3, 0, 24, 144, 96, 4, 0, 120, 1200, 1800, 400, 5, 0, 720, 10800, 28800, 16200, 1440, 6, 0, 5040, 105840, 441000, 470400, 119070, 4704, 7, 0, 40320, 1128960, 6773760, 11760000, 6021120, 762048, 14336, 8, 0, 362880, 13063680, 106686720, 274337280, 238140000, 65028096, 4408992, 41472, 9, 0
Offset: 0

Views

Author

Paul D. Hanna, Nov 17 2023

Keywords

Comments

A161633(n) = Sum_{k=0..n} T(n,k) for n >= 0.
A366232(n) = Sum_{k=0..n} T(n,k) * 2^k for n >= 0.
A366233(n) = Sum_{k=0..n} T(n,k) * 3^k for n >= 0.
A366234(n) = Sum_{k=0..n} T(n,k) * 4^k for n >= 0.
A366235(n) = Sum_{k=0..n} T(n,k) * 5^k for n >= 0.

Examples

			E.g.f. A(x,y) = 1 + x + (2*y + 2)*x^2/2! + (3*y^2 + 18*y + 6)*x^3/3! + (4*y^3 + 96*y^2 + 144*y + 24)*x^4/4! + (5*y^4 + 400*y^3 + 1800*y^2 + 1200*y + 120)*x^5/5! + (6*y^5 + 1440*y^4 + 16200*y^3 + 28800*y^2 + 10800*y + 720)*x^6/6! + (7*y^6 + 4704*y^5 + 119070*y^4 + 470400*y^3 + 441000*y^2 + 105840*y + 5040)*x^7/7! + (8*y^7 + 14336*y^6 + 762048*y^5 + 6021120*y^4 + 11760000*y^3 + 6773760*y^2 + 1128960*y + 40320)*x^8/8! + ...
This triangle of coefficients T(n,k) of x^n*y^k/n! in A(x,y) begins
 1;
 1, 0;
 2, 2, 0;
 6, 18, 3, 0;
 24, 144, 96, 4, 0;
 120, 1200, 1800, 400, 5, 0;
 720, 10800, 28800, 16200, 1440, 6, 0;
 5040, 105840, 441000, 470400, 119070, 4704, 7, 0;
 40320, 1128960, 6773760, 11760000, 6021120, 762048, 14336, 8, 0;
 362880, 13063680, 106686720, 274337280, 238140000, 65028096, 4408992, 41472, 9, 0;
 ...
		

Crossrefs

Programs

  • PARI
    {T(n,k) = n! * binomial(n+1, n-k)/(n+1) * (n-k)^k/k!}
    for(n=0,10, for(k=0,n, print1(T(n,k),", "));print(""))

Formula

T(n,k) = n! * binomial(n+1, n-k)/(n+1) * (n-k)^k / k!.
Let A(x,y)^m = Sum_{n>=0} a(n,m) * x^n/n! then a(n,m) = n!*Sum_{k=0..n} binomial(n+m, n-k)*m/(n+m) * y^k * (n-k)^k/k!.
E.g.f. A(x,y) = Sum_{n>=0} x^n/n! * Sum_{k=0..n} T(n,k)*y^k satisfies the following formulas.
(1) A(x,y) = 1 + x*A(x) * exp(x*y*A(x,y)).
(2) A(x,y) = (1/x) * Series_Reversion( x/(1 + x*exp(x*y)) ).
(3) A( x/(1 + x*exp(x*y)), y) = 1 + x*exp(x*y).
(4) A(x,y) = 1 + (m+1) * Sum{n>=1} n*(n+m)^(n-2) * x^n/n! * A(x,y)^n * exp(-(n+m-y)*x*A(x,y)) for all fixed nonnegative m.
(4.a) A(x,y) = 1 + Sum{n>=1} n^(n-1) * x^n/n! * A(x,y)^n * exp(-(n-y)*x*A(x)).
(4.b) A(x,y) = 1 + 2 * Sum{n>=1} n*(n+1)^(n-2) * x^n/n! * A(x,y)^n * exp(-(n+1-y)*x*A(x,y)).
(4.c) A(x,y) = 1 + 3 * Sum{n>=1} n*(n+2)^(n-2) * x^n/n! * A(x,y)^n * exp(-(n+2-y)*x*A(x,y)).
(4.d) A(x,y) = 1 + 4 * Sum{n>=1} n*(n+3)^(n-2) * x^n/n! * A(x,y)^n * exp(-(n+3-y)*x*A(x,y)).
(4.e) A(x,y) = 1 + 5 * Sum{n>=1} n*(n+4)^(n-2) * x^n/n! * A(x,y)^n * exp(-(n+4-y)*x*A(x,y)).