a(n) = 1 + n + n*{n/2} + n*{n/2}*{n/3} + n*{n/2}*{n/3}*{n/4} +... where {x} = [x+1/2] = round(x).

A213907

a(n) = 1 + n + n*{n/2} + n*{n/2}*{n/3} + n*{n/2}*{n/3}*{n/4} +... where {x} = [x+1/2] = round(x).

Terms

    a(0) =1a(1) =3a(2) =9a(3) =34a(4) =61a(5) =261a(6) =709a(7) =1324a(8) =4937a(9) =15040a(10) =28561a(11) =107262a(12) =248341a(13) =522445a(14) =1972363a(15) =7591936a(16) =8835345a(17) =26421129a(18) =145475533a(19) =183752250a(20) =701184621a(21) =2234736295a(22) =2996725227a(23) =15105451596a(24) =32483720761a(25) =77618520551a(26) =217809217211a(27) =625456400842

External references