Number of descents beginning and ending with an even number in all permutations of {1,2,...,n}.
A152886
Number of descents beginning and ending with an even number in all permutations of {1,2,...,n}.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =6a(4) =24a(5) =360a(6) =2160a(7) =30240a(8) =241920a(9) =3628800a(10) =36288000a(11) =598752000a(12) =7185024000a(13) =130767436800
External references
- oeis: A152886