28811

Appears in sequences

• Number of zero-sum -1..1 arrays of n elements with first and second differences also in -1..1.at n=18A201866
• Number of unlabeled balanced rooted semi-identity trees with n nodes.at n=27A306201
• Numbers k such that k![4] - 128 is prime, where k![4] = A007662(k) = quadruple factorial.at n=40A329176
• a(n) = n! * Sum_{k=1..n} 1/(k! * floor(n/k)!).at n=8A355991