a(n) = n! * [x^n] (sec(x) + tan(x))^n.

A298244

a(n) = n! * [x^n] (sec(x) + tan(x))^n.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =30a(4) =320a(5) =4400a(6) =74016a(7) =1472240a(8) =33800192a(9) =879646464a(10) =25589632000a(11) =822867814912

External references