cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A109264 Riordan array (1-x-x^2,x(1-x)).

Original entry on oeis.org

1, -1, 1, -1, -2, 1, 0, 0, -3, 1, 0, 1, 2, -4, 1, 0, 0, 1, 5, -5, 1, 0, 0, -1, -1, 9, -6, 1, 0, 0, 0, -2, -6, 14, -7, 1, 0, 0, 0, 1, -1, -15, 20, -8, 1, 0, 0, 0, 0, 3, 5, -29, 27, -9, 1, 0, 0, 0, 0, -1, 4, 20, -49, 35, -10, 1, 0, 0, 0, 0, 0, -4, -1, 49, -76, 44, -11, 1, 0, 0, 0, 0, 0, 1, -8, -21, 98, -111, 54, -12, 1
Offset: 0

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Author

Paul Barry, Jun 24 2005

Keywords

Comments

Rows sums are A109265. Diagonal sums are A109266. Inverse is A109267.

Examples

			Rows begin
1;
-1,1;
-1,-2,1;
0,0,-3,1;
0,1,2,-4,1;
0,0,1,5,-5,1;
0,0,-1,-1,9,-6,1;
		

A238160 A skewed version of triangular array A029653.

Original entry on oeis.org

1, 0, 2, 0, 1, 2, 0, 0, 3, 2, 0, 0, 1, 5, 2, 0, 0, 0, 4, 7, 2, 0, 0, 0, 1, 9, 9, 2, 0, 0, 0, 0, 5, 16, 11, 2, 0, 0, 0, 0, 1, 14, 25, 13, 2, 0, 0, 0, 0, 0, 6, 30, 36, 15, 2, 0, 0, 0, 0, 0, 1, 20, 55, 49, 17, 2, 0, 0, 0, 0, 0, 0, 7, 50, 91, 64, 19, 2, 0, 0, 0, 0, 0
Offset: 0

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Author

Philippe Deléham, Feb 18 2014

Keywords

Comments

Triangle T(n,k), 0<=k<=n, read by rows, given by (0, 1/2, -1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (2, -1, 0, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.
Row sums are Fib(n+2).
Column sums are A003945(k).
Diagonal sums are (-1)^(n+1)*A109266(n+1).
T(3*n,2*n) = A029651(n).

Examples

			Triangle begins:
1;
0, 2;
0, 1, 2;
0, 0, 3, 2;
0, 0, 1, 5, 2;
0, 0, 0, 4, 7, 2;
0, 0, 0, 1, 9, 9, 2;
0, 0, 0, 0, 5, 16, 11, 2;
0, 0, 0, 0, 1, 14, 25, 13, 2;
0, 0, 0, 0, 0, 6, 30, 36, 15, 2;
0, 0, 0, 0, 0, 1, 20, 55, 49, 17, 2;
0, 0, 0, 0, 0, 0, 7, 50, 91, 64, 19, 2;
...
		

Crossrefs

Formula

G.f.: (1+x*y)/(1-x*y-x^2*y).
T(n,k) = T(n-1,k-1) + T(n-2,k-1), T(0,0) = 1, T(1,0) = 0, T(1,1) = 2, T(n,k) = 0 if k<0 or if k>n.
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A000045(n+2), A026150(n+1), A108306(n), A164545(n), A188168(n+1) for x = 0, 1, 2, 3, 4, 5 respectively.
Showing 1-2 of 2 results.