G.f.: A(x) = exp( Sum_{n>=1} 5^n * x^n/(n*(1+x^n)) ).

Terms

a(0) =1a(1) =5a(2) =20a(3) =105a(4) =520a(5) =2580a(6) =12945a(7) =64680a(8) =323320a(9) =1616780a(10) =8083745a(11) =40418380a(12) =202092620a(13) =1010462480a(14) =5052310420a(15) =25261556205a(16) =126307777920a(17) =631538879180