|
%I #13 Aug 03 2016 18:18:43
%S 2,4,10,15,22,27,34,36,101,104,106,112,163,168,211,224,229,234,261,
%T 269,272,305,310,319,322,329,335,340,343,347,350,353,360,421,432,529,
%U 842,844,846,851,863,878,880,913,915,936,991,998
%N a(1)=2, a(n) = 1 + (smallest integer > a(n-1) with the same number of divisors as a(n-1)).
%H Harvey P. Dale, <a href="/A128513/b128513.txt">Table of n, a(n) for n = 1..1001</a>
%e a(6) = 27, which has 4 positive divisors. The next larger
%e integer with 4 divisors is 33. So a(7) = 1 + 33 = 34.
%t 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 *)
%t 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 *)
%K nonn
%O 1,1
%A _Leroy Quet_, Jun 12 2007
%E More terms from _Stefan Steinerberger_, Jun 15 2007
|
