Duplicate of A062392.

Terms

a(0) =1a(1) =15a(2) =66a(3) =190a(4) =435a(5) =861a(6) =1540a(7) =2556a(8) =4005a(9) =5995a(10) =8646a(11) =12090a(12) =16471a(13) =21945