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A175990 Irregular triangle t(n,m) = binomial(n-m-1,m+1) read by rows. 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

Row sums are A000071.

Essentially the same as A011972 (removing first column). Elimination of each 2nd row yields essentially A054142 or A121314. Interleaved with zeros one obtains A052553.

Padding with an initial column of 1's and more zeros yields A169803. Signed variants are A115139 and A124033.

LINKS

Table of n, a(n) for n=2..42.

EXAMPLE

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

t[n_, m_] = Binomial[n - (m + 1), m + 1];

a = Table[Table[t[n, m], {m, 0, Floor[(n - 1)/2]}], {n, 2, 12}];

Flatten[a]

CROSSREFS

Sequence in context: A008734 A226649 A053445 * A290982 A162517 A180876

Adjacent sequences:  A175987 A175988 A175989 * A175991 A175992 A175993

KEYWORD

nonn,tabf,easy

AUTHOR

Roger L. Bagula, Dec 06 2010

STATUS

approved

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Last modified July 20 11:28 EDT 2019. Contains 325180 sequences. (Running on oeis4.)