a(n) = (1/C(2n,0) - 1/C(2n,1) + ... + d/C(2n,2n))*L, where d = (-1)^2n, L = LCM{C(2n,0), C(2n,1),..., C(2n,2n)}.
A025535
a(n) = (1/C(2n,0) - 1/C(2n,1) + ... + d/C(2n,2n))*L, where d = (-1)^2n, L = LCM{C(2n,0), C(2n,1),..., C(2n,2n)}.
Terms
- a(0) =1a(1) =3a(2) =20a(3) =105a(4) =504a(5) =4620a(6) =51480a(7) =45045a(8) =1361360a(9) =23279256a(10) =21162960a(11) =446185740a(12) =2059318800a(13) =5736673800a(14) =155272637520
External references
- oeis: A025535