A089084 - OEIS

A089084

Numbers n such that abs ( (sum_m (m=1..n) d(m)) / n - log(n) - 2*gamma + 1) is a decreasing sequence, where d(m) is the number of divisors A000005(m) and gamma is Euler's constant A001620.

%I #19 Sep 01 2018 09:21:54

%S 1,2,3,5,7,11,17,19,23,47,89,125,131,203,219,455,1475,2867,4649,7291,

%T 36893,378878,517914,693028,923373,1835331,3147909,3356513,3506524,

%U 6782094,20454813,25494256,27802807,28081980,47214722,176344865

%N Numbers n such that abs ( (sum_m (m=1..n) d(m)) / n - log(n) - 2*gamma + 1) is a decreasing sequence, where d(m) is the number of divisors A000005(m) and gamma is Euler's constant A001620.

%D For references and links see A006218 and A089044.

%H Hugo Pfoertner, <a href="/A089084/b089084.txt">Table of n, a(n) for n = 1..46</a>

%o (PARI) s=0;r=2;for(k=1,10^7,s=s+numdiv(k);t=abs(s/k-log(k)-2*Euler+1);if(abs(t)<r,print1(k,", ");r=t)) \\ _Hugo Pfoertner_, Aug 30 2018

%Y Cf. A000005, A001620, A006218, A089044.

%K nonn

%O 1,2

%A _Hugo Pfoertner_, Dec 04 2003

%E Terms a(12) and beyond from _Hans Havermann_