0,3

Number of different orderings for n-input trees in a Free Quaternary Decision Diagram

a(0) = 1, a(n) = n*a(n-1)^4

Quartic extension of A052129 and A123851

Sequence in context: A166475 A152688 A046873 this_sequence A100540 A138076 A007861

Adjacent sequences: A164331 A164332 A164333 this_sequence A164335 A164336 A164337

nonn

David Willingham (D.Willingham(AT)wmin.ac.uk), Aug 13 2009