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A395148
Square array A(n,k), n>=0, k>=0, read by antidiagonals downwards, where A(n,k) = (2*n)! * [x^(2*n)] 1/(1 - x^2)^(k/2).
7
1, 1, 0, 1, 1, 0, 1, 2, 9, 0, 1, 3, 24, 225, 0, 1, 4, 45, 720, 11025, 0, 1, 5, 72, 1575, 40320, 893025, 0, 1, 6, 105, 2880, 99225, 3628800, 108056025, 0, 1, 7, 144, 4725, 201600, 9823275, 479001600, 18261468225, 0, 1, 8, 189, 7200, 363825, 21772800, 1404728325, 87178291200, 4108830350625, 0
OFFSET
0,8
LINKS
Paolo Xausa, Table of n, a(n) for n = 0..11324 (first 150 antidiagonals, flattened).
FORMULA
A(0,k) = 1 and A(n,k) = k*(k+2) * A(n-1,k+4) - k*(k+1) * A(n-1,k+2) for n > 0.
EXAMPLE
Square array begins:
1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, ...
0, 9, 24, 45, 72, 105, ...
0, 225, 720, 1575, 2880, 4725, ...
0, 11025, 40320, 99225, 201600, 363825, ...
0, 893025, 3628800, 9823275, 21772800, 42567525, ...
MATHEMATICA
A395148[n_, k_] := A395148[n, k] = If[n == 0, 1, k*(k+2)*A395148[n-1, k+4] - k*(k+1)*A395148[n-1, k+2]];
Table[A395148[k, n-k], {n, 0, 10}, {k, 0, n}] (* Paolo Xausa, Apr 15 2026 *)
PROG
(PARI) a(n, k) = if(n==0, 1, k*(k+2)*a(n-1, k+4)-k*(k+1)*a(n-1, k+2));
CROSSREFS
Columns k=0..4 give A000007, A001818, A010050, A079484, A327882(n+1).
Sequence in context: A197294 A385063 A384987 * A228249 A388698 A011063
KEYWORD
nonn,tabl
AUTHOR
Seiichi Manyama, Apr 14 2026
STATUS
approved