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.

A179430 Triangular matrix T where column 0 of T^m equals C(m*3^(n-1), n) at row n for n>=0, m>=0.

Original entry on oeis.org

1, 1, 1, 3, 9, 1, 84, 405, 81, 1, 17550, 121500, 32805, 729, 1, 25621596, 247203171, 82255257, 2539107, 6561, 1, 268715232324, 3543210805275, 1382411964132, 53628242751, 199290375, 59049, 1, 21091830512086620, 373203783345533355
Offset: 0

Views

Author

Paul D. Hanna, Jul 20 2010

Keywords

Examples

			Triangle T begins:
1;
1, 1;
3, 9, 1;
84, 405, 81, 1;
17550, 121500, 32805, 729, 1;
25621596, 247203171, 82255257, 2539107, 6561, 1;
268715232324, 3543210805275, 1382411964132, 53628242751, 199290375, 59049, 1;
21091830512086620, 373203783345533355, 165018275857291311, 7607829219099993, 36456526295226, 15884240049, 531441, 1; ...
where column 0 of T equals A179431(n) = C(3^(n-1), n):
[1, 1, 3, 84, 17550, 25621596, 268715232324, ...]. ...
Illustrate row n in column 0 of T^m equals C(m*3^(n-1), n) as follows.
Matrix square T^2 begins:
1;
2, 1;
15, 18, 1;
816, 1539, 162, 1;
316251, 833490, 124659, 1458, 1;
873642672, 3060203490, 585411786, 9861183, 13122, 1; ...
where column 0 of T^2 equals A179432(n) = C(2*3^(n-1), n):
[1, 2, 15, 816, 316251, 873642672, 17743125256857, ...]. ...
Matrix cube T^3 begins:
1;
3, 1;
36, 27, 1;
2925, 3402, 243, 1;
1663740, 2667411, 275562, 2187, 1;
6774333588, 14164214850, 1896890076, 21966228, 19683, 1; ...
where column 0 of T^3 equals A136393(n) = C(3^n, n):
[1, 3, 36, 2925, 1663740, 6774333588, 204208594169580, ...].
		

Crossrefs

Programs

  • PARI
    {T(n, k)=local(M=matrix(n+1, n+1, r, c, binomial(r*3^(c-2), c-1)), P); P=matrix(n+1, n+1, r, c, binomial((r+1)*3^(c-2), c-1)); (P~*M~^-1)[n+1, k+1]}