OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
t = {1}; Do[d = DivisorSigma[0, t[[-1]]]; AppendTo[t, d*Ceiling[n/d]], {n, 2, 100}]; t (* T. D. Noe, Mar 23 2011 *)
nxt[{n_, a_}]:=Module[{d=DivisorSigma[0, a]}, {n+1, d*Ceiling[(n+1)/d]}]; Transpose[ NestList[nxt, {1, 1}, 70]][[2]] (* Harvey P. Dale, Oct 14 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Jun 15 2009
EXTENSIONS
More terms from Sean A. Irvine, Mar 23 2011
STATUS
approved