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A333989
Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of (1+(k-1)*x) / (1+2*(k-1)*x+((k+1)*x)^2).
2
1, 1, 1, 1, 0, 1, 1, -1, -4, 1, 1, -2, -7, 0, 1, 1, -3, -8, 23, 16, 1, 1, -4, -7, 64, 17, 0, 1, 1, -5, -4, 117, -128, -241, -64, 1, 1, -6, 1, 176, -527, -512, 329, 0, 1, 1, -7, 8, 235, -1264, 237, 4096, 1511, 256, 1, 1, -8, 17, 288, -2399, 3776, 11753, -8192, -5983, 0, 1
OFFSET
0,9
FORMULA
T(n,k) = Sum_{j=0..n} (-k)^j * binomial(2*n,2*j).
T(0,k) = 1, T(1,k) = 1-k and T(n,k) = -2 * (k-1) * T(n-1,k) - (k+1)^2 * T(n-2,k) for n>1.
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, ...
1, 0, -1, -2, -3, -4, ...
1, -4, -7, -8, -7, -4, ...
1, 0, 23, 64, 117, 176, ...
1, 16, 17, -128, -527, -1264, ...
1, 0, -241, -512, 237, 3776, ...
MATHEMATICA
T[n_, 0] := 1; T[n_, k_] := Sum[(-k)^j * Binomial[2*n, 2*j], {j, 0, n}]; Table[T[k, n - k], {n, 0, 10}, {k, 0, n}] // Flatten (* Amiram Eldar, Sep 04 2020 *)
PROG
(PARI) {T(n, k) = sum(j=0, n, (-k)^j*binomial(2*n, 2*j))}
CROSSREFS
Main diagonal gives A333991.
Sequence in context: A204456 A143441 A279206 * A016527 A010325 A355694
KEYWORD
sign,tabl
AUTHOR
Seiichi Manyama, Sep 04 2020
STATUS
approved