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.

A375252 First Sylvester wave. Triangle read by rows: Coefficients of the numerator of the polynomial part of the partition function restricted to partitions of the integer x with parts in (1,2,...,n). (The denominators are A375251.)

Original entry on oeis.org

1, 3, 2, 47, 36, 6, 175, 135, 30, 2, 50651, 38250, 9300, 900, 30, 598731, 439810, 110250, 12320, 630, 12, 87797891, 62748420, 15840279, 1893360, 116130, 3528, 42, 706078278, 492161075, 123824862, 15302301, 1031940, 38682, 756, 6
Offset: 1

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Author

Peter Luschny, Aug 07 2024

Keywords

Examples

			Triangle starts:
  [1]         1;
  [2]         3,         2;
  [3]        47,        36,         6;
  [4]       175,       135,        30,        2;
  [5]     50651,     38250,      9300,      900,      30;
  [6]    598731,    439810,    110250,    12320,     630,    12;
  [7]  87797891,  62748420,  15840279,  1893360,  116130,  3528,  42;
  [8] 706078278, 492161075, 123824862, 15302301, 1031940, 38682, 756, 6;
.
Let A = ((a + b + c)^2 + (b*c) + (a*c) + (a*b))/6; B = a + b + c; C = 1 and W1 = (A + B*x + C*x^2)/(2*a*b*c). If (a, b, c) = (1, 2, 3) then W1([3], x) = (47 + 36*x + 6*x^2)/72. (See formulas (35), (37) and Fig. 2 in Dilcher & Vignat.)
		

Crossrefs

Cf. A375251 (denominators), A375250 (main diagonal).

Programs

  • Maple
    read(PARTITIONS):  # See Sills & Zeilberger paper.
    FirstWave := proc(n) op(pmnPC(n, x)[1]); %*denom(%) end:
    seq(print(seq(coeff(FirstWave(n), x, k), k = 0..n-1)), n = 1..9);
    # Or, standalone:
    W := proc(n) local k; exp(t*x)/mul(1 - exp(-t*k), k=1..n);
    expand(series(%, t, n+1)); coeff(%, t, -1); %*denom(%) end:
    Trow := n -> local k; seq(coeff(W(n), x, k), k = 0..n-1):
    seq(print(Trow(n)), n = 1..8);

Formula

(1/A375251(n)) * Sum_{k=0..n-1} T(n, k)*x^k = W1([n], x), where W1([n], x) denotes the first Sylvester wave restricted to parts in [n].
T(n, k) = [x^k] p(n) where p(n) = W(n)*denominator(W(n)) and W(n) = [t^(-1)] exp(t*x)/Product_{k=1..n}(1 - exp(-t*k)).