OFFSET
0,2
COMMENTS
Main diagonal of A082037
a(n) = total number of runs when each permutation on [n+1] is split into maximal monotone runs. (A monotone run is a sequence of consecutive entries whose differences are all 1 or all -1. Example: 34-1-765-2 contributes 4 runs to a(6) as indicated.) - David Callan, Nov 16 2003
a(n) is also the number of distinct planar embeddings of the (n+1)-Sierpinski gasket graph. - Eric W. Weisstein, May 21 2024
LINKS
Eric Weisstein's World of Mathematics, Planar Embedding.
Eric Weisstein's World of Mathematics, Sierpinski Gasket Graph.
FORMULA
(n^2-2*n+2)*a(n) -n*(n^2+1)*a(n-1)=0. - R. J. Mathar, Dec 03 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 02 2003
STATUS
approved