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A126125
Triangle equal to the matrix square of the triangle binomial(n,floor((n+1-(-1)^(n+k)*(k+1))/2)).
1
1, 2, 1, 5, 2, 1, 11, 7, 2, 1, 27, 15, 9, 2, 1, 61, 44, 19, 11, 2, 1, 149, 97, 65, 23, 13, 2, 1, 342, 267, 141, 90, 27, 15, 2, 1, 835, 599, 433, 193, 119, 31, 17, 2, 1, 1939, 1598, 956, 655, 253, 152, 35, 19, 2, 1, 4740, 3631
OFFSET
0,2
COMMENTS
The triangular view of A061554 is:
1;
1, 1;
2, 1, 1;
3, 3, 1, 1;
6, 4, 4, 1, 1;
The matrix square of this (infinite) triangle is this triangle here.
EXAMPLE
First few rows of the triangle are:
1;
2, 1;
5, 2, 1;
11, 7, 2, 1;
27, 15, 9, 2, 1;
61, 44, 19, 11, 2, 1;
..,
MAPLE
A061554 := proc(n, k) local m ; m := floor((n+1)/2 - (-1)^(n-k)*(k+1)/2) ; binomial(n, m) ; end proc:
A126125 := proc(n, k) add(A061554(n, j)*A061554(j, k), j=k..n) ; end proc: # R. J. Mathar, Sep 17 2011
CROSSREFS
Cf. A061554, A127358 (row sums).
Sequence in context: A361681 A105084 A375100 * A221876 A128514 A323953
KEYWORD
tabl,easy,nonn
AUTHOR
Gary W. Adamson, Dec 17 2006
STATUS
approved