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A125230
Triangle T(n,k) (0<=k<=n) read by rows in which column k contains the binomial transform of the sequence of k 0's, (k+1) 1's, followed by 0's.
1
1, 1, 1, 1, 3, 1, 1, 6, 4, 1, 1, 10, 11, 5, 1, 1, 15, 25, 16, 6, 1, 1, 21, 50, 42, 22, 7, 1, 1, 28, 91, 98, 64, 29, 8, 1, 1, 36, 154, 210, 163, 93, 37, 9, 1, 1, 45, 246, 420, 381, 256, 130, 46, 10, 1, 1, 55, 375, 792, 837, 638, 386, 176, 56, 11, 1, 1, 66, 550, 1419, 1749, 1485, 1024
OFFSET
0,5
COMMENTS
A125231 is another triangle with the same row sums A045623: (1, 2, 5, 12, 28, 64, 144, 320...).
FORMULA
T(n,k) = Sum_{j=k..min(2*k,n)} C(n,j).
EXAMPLE
T(5,2) = C(5,2) + C(5,3) + C(5,4) = 10 + 10 + 5 = 25.
First few rows of the triangle are:
1
1 1
1 3 1
1 6 4 1
1 10 11 5 1
1 15 25 16 6 1
MAPLE
T:= (n, k)-> add (binomial (n, j), j=k..min(2*k, n)): seq (seq (T(n, k), k=0..n), n=0..12);
CROSSREFS
Cf. A007318, A125231. Columns k=0-3 give: A000012, A000217, A006522(n+1), A055796(n-3). Row sums give: A045623.
Sequence in context: A133567 A271665 A184049 * A208334 A162430 A305059
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Nov 24 2006
EXTENSIONS
Edited with more terms and Maple program by Alois P. Heinz, Oct 16 2009
STATUS
approved