A178013 Number of permutations of 2 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/3)] (3-way heap)

1, 3, 12, 108, 1944, 38718, 994392, 38570364, 1447995258, 79481475504, 7085744965872

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Crossrefs

Simple 2-way heap A056971

Sequence in context: A293126 A080447 A127059 * A068099 A224818 A032113

Adjacent sequences: A178010 A178011 A178012 * A178014 A178015 A178016

Keyword

nonn

Author

R. H. Hardin May 17 2010

Status

approved