A179544 - OEIS

%I #24 Oct 30 2013 19:41:08

%S 1,1,2,5,12,30,80,219,614,1766,5206,15646,47834,148602,468110,1492841,

%T 4814682,15686156,51575438

%N Number of Dyck paths of semilength n for which the multiset of ascent lengths and the multiset of descent lengths are the same partition of n.

%e For n=4 the paths UUUDDUDD and UUDUUDDD fail the definition because {2,2} != {3,1} so a(4) = 12 rather than Catalan(4)=14.

%K nonn,more

%O 0,3

%A _David Scambler_, Jan 08 2011

%E a(15)-a(18) from _Alois P. Heinz_, May 07 2012