A175265 - OEIS

A175265

a(1)=1. a(n) = the smallest integer > a(n-1) where |d(a(n)) - d(a(n-1))| = 1; d(n) is the number of divisors of n.

%I #9 Mar 11 2014 01:32:51

%S 1,2,4,5,9,10,16,18,64,66,100,102,196,208,225,230,256,258,441,442,484,

%T 488,676,678,729,730,1089,1090,1156,1158,1225,1235,1444,1446,1521,

%U 1526,2116,2118,2601,2607,3025,3026,3249,3262,3364,3367,3844,3846,4225,4233

%N a(1)=1. a(n) = the smallest integer > a(n-1) where |d(a(n)) - d(a(n-1))| = 1; d(n) is the number of divisors of n.

%H Harvey P. Dale, <a href="/A175265/b175265.txt">Table of n, a(n) for n = 1..1000</a>

%t nxt[n_]:=Module[{k=n+1},While[Abs[DivisorSigma[0,n]-DivisorSigma[0,k]] != 1,k++];k]; NestList[nxt,1,50] (* _Harvey P. Dale_, Oct 10 2012 *)

%Y A175266

%K nonn

%O 1,2

%A _Leroy Quet_, Mar 18 2010

%E More terms from _Jon E. Schoenfield_, Jun 13 2010