a(n) = (3*n)!/n! * [x^(3*n)] sinh(x)^n.A383837a(n) = (3*n)!/n! * [x^(3*n)] sinh(x)^n.Terms a(0) =1a(1) =1a(2) =16a(3) =820a(4) =87296a(5) =15857205a(6) =4390088704External referencesoeis: A383837