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 A291373 #23 Sep 04 2025 10:54:10 %S A291373 2,0,6,841,0,1722,30018,0,0,0,4057230930,0,0, %T A291373 92568222856376123089883329681 %N A291373 a(n) is the smallest number k such that A001065(k) = A002110(n), or 0 if no such k exists. %C A291373 For n in A057704, 0 < a(n) <= (A002110(n)-1)^2. - _Max Alekseyev_, Sep 01 2025 %F A291373 a(n) = A070015(A002110(n)). - _Michel Marcus_, Aug 25 2017 %e A291373 a(5) = 1722 because sigma(1722) - 1722 = 2*3*5*7*11 = A002110(5) and 1722 is the least number with this property. %Y A291373 Cf. A001065, A002110, A057704, A070015, A116017, A153076, A235710, A244444, A279359, A291356, A378099. %K A291373 nonn,hard,more,changed %O A291373 0,1 %A A291373 _Altug Alkan_, Aug 23 2017 %E A291373 a(7) and a(10) from _Giovanni Resta_, Aug 23 2017 %E A291373 a(8)-a(9), a(11)-a(13) from _Max Alekseyev_, Sep 04 2025