a(n) = 1 + 2*n + 2^2*n*[n/2] + 2^3*n*[n/2]*[n/3] + 2^4*n*[n/2]*[n/3]*[n/4] + ... where [x]=floor(x).

A208060

a(n) = 1 + 2*n + 2^2*n*[n/2] + 2^3*n*[n/2]*[n/3] + 2^4*n*[n/2]*[n/3]*[n/4] + ... where [x]=floor(x).

Terms

    a(0) =1a(1) =3a(2) =13a(3) =43a(4) =233a(5) =611a(6) =4405a(7) =10515a(8) =64145a(9) =218755a(10) =1215821a(11) =2689083a(12) =28162105a(13) =61179795a(14) =307475813a(15) =1236997051a(16) =8042542625a(17) =17101581699a(18) =146671231501a(19) =309740445795

External references