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A091562
Triangle read by rows, related to Pascal's triangle, starting with 1, 0, 0.
5
1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 2, 5, 7, 5, 2, 3, 10, 17, 17, 10, 3, 5, 20, 41, 51, 41, 20, 5, 8, 38, 91, 136, 136, 91, 38, 8, 13, 71, 195, 339, 405, 339, 195, 71, 13, 21, 130, 403, 799, 1107, 1107, 799, 403, 130, 21, 34, 235, 812, 1807, 2845, 3297, 2845, 1807, 812, 235, 34
OFFSET
0,8
FORMULA
T(n, k) = T(n-1, k) + T(n-1, k-1) + T(n-2, k) + T(n-2, k-1) + T(n-2, k-2) for n >= 2, k >= 0, with initial conditions specified by first two rows.
G.f.: A(x, y) = (1-x-x*y)/(1-x-x*y-x^2-x^2*y-x^2*y^2).
EXAMPLE
Triangle begins:
1;
0,0;
1,1,1;
1,2,2,1;
2,5,7,5,2;
...
CROSSREFS
Row sums: A054878, column 0: A000045(n-1), column 1: A001629.
Cf. A090171, A090172, A090173, A090174, A091533, A205575 (same recurrence).
Cf. A090172.
Sequence in context: A059594 A183760 A125678 * A106585 A057227 A335190
KEYWORD
nonn,easy,tabl
AUTHOR
Christian G. Bower, Jan 20 2004
STATUS
approved