(n-1)-st elementary symmetric function of {1, 2, 2, 3, 3, 4, 4, 5, 5, ..., floor(1+n/2)}.
A203152
(n-1)-st elementary symmetric function of {1, 2, 2, 3, 3, 4, 4, 5, 5, ..., floor(1+n/2)}.
Terms
- a(0) =1a(1) =3a(2) =8a(3) =28a(4) =96a(5) =420a(6) =1824a(7) =9696a(8) =51360a(9) =322560a(10) =2021760a(11) =14670720a(12) =106323840a(13) =875992320a(14) =7211151360a(15) =66526064640a(16) =613365903360
External references
- oeis: A203152