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A123934
Triangle T(n,k), 1<=k<=n :forms the odd-indexed trinomial coefficients (A027907).
0
1, 2, 2, 3, 7, 3, 4, 16, 16, 4, 5, 30, 51, 30, 5, 6, 50, 126, 126, 50, 6, 7, 77, 266, 393, 266, 77, 7
OFFSET
1,2
FORMULA
Sum_{k, 1<=k<=n}T(n,k)=A003462(n)=(3^n-1)/2.
EXAMPLE
Triangle begins:
1;
2, 2;
3, 7, 3;
4, 16, 16, 4;
5, 30, 51, 30, 5;
6, 50, 126, 126, 50, 6;
7, 77, 266, 393, 266, 77, 7;
CROSSREFS
Cf. A056241.
Sequence in context: A183442 A296019 A134232 * A363365 A208151 A203362
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Oct 30 2006
STATUS
approved