|
|
A121336
|
|
Triangle, read by rows, where T(n,k) = C( n*(n+1)/2 + n-k + 2, n-k), for n>=k>=0.
|
|
5
|
|
|
1, 4, 1, 21, 6, 1, 165, 45, 9, 1, 1820, 455, 91, 13, 1, 26334, 5985, 1140, 171, 18, 1, 475020, 98280, 17550, 2600, 300, 24, 1, 10295472, 1947792, 324632, 46376, 5456, 496, 31, 1, 260932815, 45379620, 7059052, 962598, 111930, 10660, 780, 39, 1
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
A triangle having similar properties and complementary construction is the dual triangle A122177.
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
Triangle begins:
1;
4, 1;
21, 6, 1;
165, 45, 9, 1;
1820, 455, 91, 13, 1;
26334, 5985, 1140, 171, 18, 1;
475020, 98280, 17550, 2600, 300, 24, 1;
10295472, 1947792, 324632, 46376, 5456, 496, 31, 1;
260932815, 45379620, 7059052, 962598, 111930, 10660, 780, 39, 1; ...
|
|
PROG
|
(PARI) T(n, k)=binomial(n*(n+1)/2+n-k+2, n-k)
|
|
CROSSREFS
|
|
|
KEYWORD
|
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|