A136733 Square array, read by antidiagonals, where T(n,k) = T(n,k-1) + T(n-1,k+n) for n>0, k>0, such that T(n,0) = T(n-1,n) for n>0 with T(0,k)=1 for k>=0.

1, 1, 1, 3, 2, 1, 18, 7, 3, 1, 170, 43, 12, 4, 1, 2220, 403, 76, 18, 5, 1, 37149, 5188, 711, 118, 25, 6, 1, 758814, 85569, 9054, 1107, 170, 33, 7, 1, 18301950, 1725291, 147471, 13986, 1605, 233, 42, 8, 1, 508907970, 41145705, 2938176, 225363, 20171, 2220, 308

Offset

0,4

Links

Table of n, a(n) for n=0..51.

Example

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,...];
(1,2), 3, 4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,...;
(3,7,12), 18, 25,33,42,52,63,75,88,102,117,133,150,168,187,207,228,...;
(18,43,76,118), 170, 233,308,396,498,615,748,898,1066,1253,1460,...;
(170,403,711,1107,1605), 2220, 2968,3866,4932,6185,7645,9333,11271,...;
(2220,5188,9054,13986,20171,27816), 37149, 48420,61902,77892,96712,...;
(37149,85569,147471,225363,322075,440785,585046), 758814, 966477,...;
(758814,1725291,2938176,4441557,6285390,8526057,11226958,14459138), ...;
where the rows are generated as follows.
Start row 0 with all 1's; from then on,
remove the first n+1 terms (shown in parenthesis) from row n
and then take partial sums to yield row n+1.
Note the first upper diagonal forms column 0 and equals A101483:
[1,1,3,18,170,2220,37149,758814,18301950,508907970,16023271660,...]
which equals column 2 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'.

Prog

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

Crossrefs

Cf. A101479; columns: A101483, A121418, A121421; A121425 (main diagonal); variants: A136730, A136737.

Sequence in context: A106208 A350710 A129377 * A117269 A291080 A107862

Adjacent sequences: A136730 A136731 A136732 * A136734 A136735 A136736

Keyword

nonn,tabl

Author

Paul D. Hanna, Jan 19 2008

Status

approved