A067303 Even-indexed members of A067302.

1, 18, 1752, 282304, 54547200, 11478167040, 2533556365312, 576271774875648, 133776598692003840, 31513560479297044480, 7505638177922587557888, 1802924878727702252617728, 436026430783762289982963712

Offset: 0

Author

Wolfdieter Lang, Feb 05 2002

Keywords

• nonn
• easy

Crossrefs

Cf. A067322 (odd-indexed members of A067302).

Formula

a(n) = A067302(2n) = (n+1)*A067297(2*n).

G.f.: (x*(d/dx)A(x) + A(x)) with A(x) g.f. of A067320.