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.

A152400 Triangle T, read by rows, where column k of T = column 0 of matrix power T^(k+1) for k>0, with column 0 of T = unsigned column 0 of T^-1 (shifted).

Original entry on oeis.org

1, 1, 1, 3, 2, 1, 14, 8, 3, 1, 86, 45, 15, 4, 1, 645, 318, 99, 24, 5, 1, 5662, 2671, 794, 182, 35, 6, 1, 56632, 25805, 7414, 1636, 300, 48, 7, 1, 633545, 280609, 78507, 16844, 2990, 459, 63, 8, 1, 7820115, 3381993, 926026, 194384, 33685, 5026, 665, 80, 9, 1
Offset: 0

Views

Author

Paul D. Hanna, Dec 05 2008

Keywords

Examples

			Triangle T begins:
1;
1, 1;
3, 2, 1;
14, 8, 3, 1;
86, 45, 15, 4, 1;
645, 318, 99, 24, 5, 1;
5662, 2671, 794, 182, 35, 6, 1;
56632, 25805, 7414, 1636, 300, 48, 7, 1;
633545, 280609, 78507, 16844, 2990, 459, 63, 8, 1;
7820115, 3381993, 926026, 194384, 33685, 5026, 665, 80, 9, 1;...
where column k of T = column 0 of T^(k+1) for k>0
and column 0 of T = unsigned column 0 of T^-1 (shifted).
Amazingly, column k of T^(j+1) = column j of T^(k+1) for j>=0, k>=0.
Matrix inverse T^-1 begins:
1;
-1, 1;
-1, -2, 1;
-3, -2, -3, 1;
-14, -7, -3, -4, 1;
-86, -37, -12, -4, -5, 1;
-645, -252, -71, -18, -5, -6, 1;...
where unsigned column 0 of T^-1 = column 0 of T (shifted).
Matrix square T^2 begins:
1;
2, 1;
8, 4, 1;
45, 22, 6, 1;
318, 152, 42, 8, 1;
2671, 1251, 345, 68, 10, 1;
25805, 11869, 3253, 648, 100, 12, 1;
280609, 126987, 34546, 6898, 1085, 138, 14, 1;...
where column 0 of T^2 = column 1 of T,
and column 2 of T^2 = column 1 of T^3.
Matrix cube T^3 begins:
1;
3, 1;
15, 6, 1;
99, 42, 9, 1;
794, 345, 81, 12, 1;
7414, 3253, 798, 132, 15, 1;
78507, 34546, 8679, 1518, 195, 18, 1;
926026, 407171, 103707, 18734, 2565, 270, 21, 1;...
where column 0 of T^3 = column 2 of T,
and column 3 of T^3 = column 2 of T^4.
Matrix power T^4 begins:
1;
4, 1;
24, 8, 1;
182, 68, 12, 1;
1636, 648, 132, 16, 1;
16844, 6898, 1518, 216, 20, 1;
194384, 81218, 18734, 2912, 320, 24, 1;
2476868, 1047638, 249202, 40932, 4950, 444, 28, 1;...
where column 0 of T^4 = column 3 of T,
and column 2 of T^4 = column 3 of T^3.
Related triangle A127714 begins:
1;
1, 1, 1;
1, 2, 2, 3, 3, 3;
1, 3, 5, 5, 8, 11, 11, 14, 14, 14;
1, 4, 9, 14, 14, 22, 33, 44, 44, 58, 72, 72, 86, 86, 86;...
where right border = column 0 of this triangle A152400.
		

Crossrefs

Cf. related triangles: A152405, A127714.

Programs

  • PARI
    T(n, k)=if(k>n || n<0,0, if(k==n,1, if(k==0,sum(j=1,n,T(n,j)*T(j-1,0)), sum(j=0,n-k,T(n-k, j)*T(j+k-1, k-1)));))

Formula

Column k of T^(j+1) = column j of T^(k+1) for all j>=0, k>=0.
Column k: T(n,k) = Sum_{j=0..n-k} T(n-k,j)*T(j+k-1,k-1) for n>=k>0.
Column 0: T(n,0) = Sum_{j=1..n} T(n,j)*T(j-1,0) for n>=0.