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A372991
a(n) = (2n)!/(a(n-1)*a(n-2)), where a(0)=1, a(1) = 1.
0
1, 1, 24, 30, 56, 2160, 3960, 10192, 518400, 1211760, 3872960, 239500800, 668891520, 2517424000, 181062604800, 581935622400, 2497284608000, 203152242585600, 733238884224000, 3511182158848000, 316917498433536000, 1262637358633728000, 6643156644540416000
OFFSET
0,3
FORMULA
Conjecture D-finite with recurrence a(n) -2*n*(2*n-1)*a(n-3)=0. - R. J. Mathar, Jul 16 2024
MATHEMATICA
a[0] = 1; a[1] = 1;
a[n_] := a[n] = (2n)!/(a[n - 1]*a[n - 2]);
Table[a[n], {n, 0, 24}]
CROSSREFS
Cf. A000142.
Sequence in context: A334790 A228875 A175258 * A333122 A135045 A109321
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jul 15 2024
STATUS
approved