Number of descents beginning with an even number and ending with an odd number in all permutations of {1,2,...,n}.
A152887
Number of descents beginning with an even number and ending with an odd number in all permutations of {1,2,...,n}.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =18a(4) =72a(5) =720a(6) =4320a(7) =50400a(8) =403200a(9) =5443200a(10) =54432000a(11) =838252800a(12) =10059033600a(13) =174356582400
External references
- oeis: A152887