a(n) = 1 + n + n[n/2] + n[n/2][n/3] +... + n[n/2][n/3]...[n/n], where [x]=ceiling(x).

A075887

a(n) = 1 + n + n[n/2] + n[n/2][n/3] +... + n[n/2][n/3]...[n/n], where [x]=ceiling(x).

Terms

    a(0) =1a(1) =2a(2) =5a(3) =16a(4) =45a(5) =171a(6) =421a(7) =1968a(8) =4553a(9) =19225a(10) =57261a(11) =226854a(12) =496309a(13) =3136420a(14) =6764563a(15) =24850336a(16) =84877201a(17) =380461599a(18) =805949533a(19) =4411165990a(20) =9288196621a(21) =48275465722a(22) =154143694937a(23) =527401107276

External references