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.

A330778 Triangle read by rows: T(n,k) is the number of balanced reduced multisystems of weight n with maximum depth and atoms colored using exactly k colors.

Original entry on oeis.org

1, 1, 1, 1, 4, 3, 2, 17, 33, 18, 5, 86, 321, 420, 180, 16, 520, 3306, 7752, 7650, 2700, 61, 3682, 37533, 140172, 238560, 189000, 56700, 272, 30050, 473604, 2644356, 6899070, 9196740, 6085800, 1587600, 1385, 278414, 6630909, 53244180, 199775820, 398328480, 435954960, 247665600, 57153600
Offset: 1

Views

Author

Andrew Howroyd, Dec 30 2019

Keywords

Examples

			Triangle begins:
    1;
    1,     1;
    1,     4,      3;
    2,    17,     33,      18;
    5,    86,    321,     420,     180;
   16,   520,   3306,    7752,    7650,    2700;
   61,  3682,  37533,  140172,  238560,  189000,   56700;
  272, 30050, 473604, 2644356, 6899070, 9196740, 6085800, 1587600;
  ...
		

Crossrefs

Column 1 is A000111.
Main diagonal is A006472.
Row sums are A330676.
Cf. A330776.

Programs

  • PARI
    EulerT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v, n, 1/n))))-1, -#v)}
    R(n, k)={my(v=vector(n), u=vector(n)); v[1]=k; for(n=1, #v, for(i=n, #v, u[i] += v[i]*(-1)^(i-n)*binomial(i-1, n-1)); v=EulerT(v)); u}
    M(n)={my(v=vector(n, k, R(n, k)~)); Mat(vector(n, k, sum(i=1, k, (-1)^(k-i)*binomial(k, i)*v[i])))}
    {my(T=M(10)); for(n=1, #T~, print(T[n, 1..n]))}