E.g.f.: Product_{n>=1} 1/(1 - tanh(x^n/n)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =9a(4) =40a(5) =200a(6) =1286a(7) =9002a(8) =74712a(9) =672408a(10) =6892312a(11) =75815432a(12) =925733216a(13) =12034531808a(14) =170656068480