VOOZH about

URL: https://oeis.org/A175990

⇱ A175990 - OEIS

login
A175990
Irregular triangle read by rows: t(n,m) = binomial(n-m-1,m+1) for 0 <= m <= floor((n-1)/2).
0
1, 2, 0, 3, 1, 4, 3, 0, 5, 6, 1, 6, 10, 4, 0, 7, 15, 10, 1, 8, 21, 20, 5, 0, 9, 28, 35, 15, 1, 10, 36, 56, 35, 6, 0, 11, 45, 84, 70, 21, 1, 12, 55, 120, 126, 56, 7, 0, 13, 66, 165, 210, 126, 28, 1, 14, 78, 220, 330, 252, 84, 8, 0, 15, 91, 286, 495, 462, 210, 36, 1, 16, 105, 364, 715, 792, 462, 120, 9, 0, 17, 120
OFFSET
2,2
EXAMPLE
Triangle begins:
1;
2, 0;
3, 1;
4, 3, 0;
5, 6, 1;
6, 10, 4, 0;
7, 15, 10, 1;
8, 21, 20, 5, 0;
9, 28, 35, 15, 1;
10, 36, 56, 35, 6, 0;
11, 45, 84, 70, 21, 1;
MATHEMATICA
Table[Binomial[n-m-1, m+1], {n, 2, 15}, {m, 0, Floor[(n-1)/2]}]//Flatten (* Harvey P. Dale, May 08 2023 *)
CROSSREFS
Row sums are A000071.
Essentially the same as A011973 (removing first column). Elimination of each 2nd row yields essentially A054142 or A121314. Interleaving with zeros gives A052553.
Padding with an initial column of 1's and more zeros yields A169803. Signed variants are A115139 and A124033.
Sequence in context: A008734 A226649 A053445 * A290982 A346034 A353949
KEYWORD
nonn,tabf,easy,less
AUTHOR
Roger L. Bagula, Dec 06 2010
EXTENSIONS
Definition clarified by Harvey P. Dale, May 08 2023
STATUS
approved