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 A073722 #11 Dec 16 2024 22:18:54
%S A073722 2,4,10,8,17,42,23,111,32,59,31,67,49,110,63,60,82,84,89,75,191,98,
%T A073722 141,97,101,256,171,169,148,144,140,159,143,222,220,172,206,2124,183,
%U A073722 315,263,567,201,358,204,470,243,391,264,563,295,382,290,285,313,324,307
%N A073722 Least k such that sigma(k) mod primepi(k) = n or zero if no such number exists.
%H A073722 Sean A. Irvine, <a href="/A073722/b073722.txt">Table of n, a(n) for n = 0..10000</a>
%F A073722 a(n) = min{x: A000203(x) mod A000720(x) = n}.
%e A073722 n=8: a(8)=32 since sigma(32)=63, primepi(32)=11, and 63 mod 11 = 8.
%t A073722 t=Table[0, {100}]; Do[s=Mod[DivisorSigma[1, n], PrimePi[n]]; If[s<101&&t[[s]]==0, t[[s]]=n], {n, 2, 10000}]; t
%Y A073722 Cf. A000203, A000720, A072548, A073721-A073724.
%K A073722 nonn
%O A073722 0,1
%A A073722 _Labos Elemer_, Aug 05 2002
%E A073722 a(0)=2 inserted by _Sean A. Irvine_, Dec 16 2024