cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A068546 Numbers k such that k*tau(k)>4*prime(k).

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%I A068546 #13 May 14 2025 16:40:35
%S A068546 840,1260,1440,1680,1800,1980,2016,2100,2160,2340,2400,2520,2640,2700,
%T A068546 2880,3024,3120,3240,3360,3600,3696,3780,3960,4032,4080,4200,4320,
%U A068546 4368,4536,4560,4620,4680,4752,4800,5040,5280,5400,5460,5520,5544,5616,5670
%N A068546 Numbers k such that k*tau(k)>4*prime(k).
%H A068546 Robert Israel, <a href="/A068546/b068546.txt">Table of n, a(n) for n = 1..10000</a>
%p A068546 R:= NULL: count:= 0: p:= 0:
%p A068546 for n from 1 while count < 100 do
%p A068546   p:= nextprime(p);
%p A068546   if n * numtheory:-tau(n) > 4 * p then R:= R, n; count:= count+1;  fi;
%p A068546 od:
%p A068546 R; # _Robert Israel_, May 14 2025
%t A068546 Select[Range[6000],# DivisorSigma[0,#]>4 Prime[#]&] (* _Harvey P. Dale_, Sep 12 2020 *)
%K A068546 easy,nonn
%O A068546 1,1
%A A068546 _Benoit Cloitre_, Mar 22 2002