a(n) = Sum_{permutations p of [n]} des(p^2), where des(p) is the number of descents of p.
A385366
a(n) = Sum_{permutations p of [n]} des(p^2), where des(p) is the number of descents of p.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =24a(4) =192a(5) =1560a(6) =13680a(7) =131040a(8) =1370880a(9) =15603840a(10) =192326400a(11) =2554675200a(12) =36404121600a(13) =554204851200
External references
- oeis: A385366