2554675200
domain: N
Appears in sequences
- Expansion of tanh(log(1+1/x)).at n=11A009769
- Denominators of the coefficients of the series for InverseErf(x).at n=5A122551
- E.g.f.: -log( sqrt(1-x^2) - x ).at n=11A194349
- a(0)=1; thereafter a(n) = n*a(n-1) if n is even, otherwise a(n) = 2*n*a(n-1).at n=11A232205
- a(n) = Sum_{permutations p of [n]} des(p^2), where des(p) is the number of descents of p.at n=11A385366