OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1001
EXAMPLE
a(6) = 27, which has 4 positive divisors. The next larger
integer with 4 divisors is 33. So a(7) = 1 + 33 = 34.
MATHEMATICA
a = {2}; n = 3; While[n < 1000, If[Length[Divisors[n]] == Length[Divisors[a[[ -1]]]], AppendTo[a, n + 1]; n++; ]; n++ ]; a (* Stefan Steinerberger, Jun 15 2007 *)
nxt[n_]:=Module[{k=n+1, ds=DivisorSigma[0, n]}, While[DivisorSigma[ 0, k] != ds, k++]; k+1]; NestList[nxt, 2, 50] (* Harvey P. Dale, Aug 03 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Jun 12 2007
EXTENSIONS
More terms from Stefan Steinerberger, Jun 15 2007
STATUS
approved