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.

A136730 Square array, read by antidiagonals, where T(n,k) = T(n,k-1) + T(n-1,k+n-1) for n>0, k>0, such that T(n,0) = T(n-1,n-1) for n>0 with T(0,k)=1 for k>=0.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 9, 5, 3, 1, 70, 23, 9, 4, 1, 795, 175, 43, 14, 5, 1, 11961, 1935, 324, 70, 20, 6, 1, 224504, 28432, 3510, 527, 105, 27, 7, 1, 5051866, 523290, 50528, 5624, 795, 149, 35, 8, 1, 132523155, 11587072, 913377, 79553, 8396, 1140, 203, 44, 9, 1, 3969912160
Offset: 0

Views

Author

Paul D. Hanna, Jan 19 2008

Keywords

Examples

			The square array begins:
1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,...];
(1), 2, 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,...;
(2,5), 9, 14,20,27,35,44,54,65,77,90,104,119,135,152,170,189,209,230,..;
(9,23,43), 70, 105,149,203,268,345,435,539,658,793,945,1115,1304,1513,.;
(70,175,324,527), 795, 1140,1575,2114,2772,3565,4510,5625,6929,8442,...;
(795,1935,3510,5624,8396), 11961, 16471,22096,29025,37467,47652,59832,..;
(11961,28432,50528,79553,117020,164672), 224504, 298786,390087,501300,..;
(224504,523290,913377,1414677,2050345,2847156,3835910), 5051866, 6535206,.;
(5051866,11587072,19918602,30410985,43486800,59633775,79412515,103464895),.;
where the rows are generated as follows.
Start row 0 with all 1's; from then on,
remove the first n terms (shown in parenthesis) from row n
and then take partial sums to yield row n+1.
Note that the main diagonal forms column 0 and equals A101482:
[1,1,2,9,70,795,11961,224504,5051866,132523155,3969912160,...]
which equals column 1 of triangle A101479:
1;
1, 1;
1, 1, 1;
3, 2, 1, 1;
19, 9, 3, 1, 1;
191, 70, 18, 4, 1, 1;
2646, 795, 170, 30, 5, 1, 1;
46737, 11961, 2220, 335, 45, 6, 1, 1;
1003150, 224504, 37149, 4984, 581, 63, 7, 1, 1; ...
where row n equals row (n-1) of T^(n-1) with appended '1'.
		

Crossrefs

Cf. A101479; columns: A101482, A136731, A136732; variants: A136733, A136737.

Programs

  • PARI
    {T(n,k)=if(k<0,0,if(n==0,1,T(n,k-1) + T(n-1,k+n-1)))}