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.
%I A073803 #22 Mar 07 2025 02:56:06
%S A073803 3,5,6,7,10,11,13,14,15,17,19,20,21,22,23,24,26,27,28,29,30,31,33,34,
%T A073803 35,37,38,39,40,41,42,43,44,45,46,47,49,51,53,54,55,56,57,58,59,60,61,
%U A073803 62,63,65,66,67,68,69,70,71,73,74,76,77,78,79,82,83,85,86,87,88,89,91
%N A073803 Numbers k such that the number of divisors of k is smaller than that of sigma(k).
%H A073803 Robert Israel, <a href="/A073803/b073803.txt">Table of n, a(n) for n = 1..10000</a>
%F A073803 Solutions to A000005(x) < A062068(x) = A000005(A000203(x)).
%e A073803 k = 96: divisors(96) = {1,2,3,4,6,8,12,16,24,32,48,96}, 12 divisors; divisors(sigma(96)) = {1,2,3,4,6,7,9,12,14,18,21,28,36,42,63,84,126,252}, 18 divisors; 12 < 18, so 96 is a term.
%p A073803 filter:= proc(n) uses numtheory; tau(n) < tau(sigma(n)) end proc:
%p A073803 select(filter, [$1..100]); # _Robert Israel_, Aug 03 2020
%t A073803 Do[s=DivisorSigma[0, DivisorSigma[1, n]]; s0=DivisorSigma[0, n]; If[Greater[s0, s], Print[n]], {n, 1, 1000}]
%t A073803 Select[Range[100],DivisorSigma[0,#]<DivisorSigma[0,DivisorSigma[1,#]]&] (* _Harvey P. Dale_, Sep 22 2019 *)
%o A073803 (PARI) isok(k) = {my(f = factor(k)); numdiv(f) < numdiv(sigma(f));} \\ _Amiram Eldar_, Mar 07 2025
%Y A073803 Cf. A000005, A000203, A062068, A073802, A073804, A037197.
%K A073803 nonn
%O A073803 1,1
%A A073803 _Labos Elemer_, Aug 13 2002