G.f.: exp( Sum_{n>=1} A055457(n) * 5^A055457(n) * x^n/n ) where 5^A055457(n) exactly divides 5*n.

Terms

a(0) =1a(1) =5a(2) =15a(3) =35a(4) =70a(5) =135a(6) =255a(7) =465a(8) =810a(9) =1345a(10) =2180a(11) =3480a(12) =5465a(13) =8410a(14) =12645a(15) =18720a(16) =27405a(17) =39690a(18) =56785a(19) =80120a(20) =111840a(21) =154805a(22) =212590a(23) =289485a(24) =390495a(25) =522640a(26) =694955a(27) =918490a(28) =1206310a(29) =1573495