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 A329460 #15 Apr 20 2024 07:43:07
%S A329460 561,62745,576480525985,1886616373665,3193231538989185,
%T A329460 11947816523586945,101817952350880305,171800042106877185
%N A329460 Carmichael numbers k that have an abundancy index sigma(k)/k that is larger than the abundancy index of all smaller Carmichael numbers.
%C A329460 The corresponding rounded values of sigma(k)/k are 1.540, 1.652, 1.665, 1.794, 1.794, 1.815, 1.816, 1.893, ...
%C A329460 Do abundant Carmichael numbers exist?
%C A329460 Abundant Carmichael numbers do exist. The prime factorization of such a number is: 5 * 7 * 13 * 17 * 19 * 23 * 37 * 59 * 67 * 73 * 83 * 89 * 97 * 109 * 163 * 193 * 199 * 233 * 257 * 349 * 353 * 397 * 433 * 523 * 739 * 929 * 1153 * 2593 * 2953 * 3169 * 5569 * 7873 * 9397 * 70849 * 313897. - _Daniel Suteu_, Aug 16 2020
%C A329460 a(9) > 10^22. - _Amiram Eldar_, Apr 20 2024
%t A329460 carmichaelQ[n_] := CompositeQ[n] && Divisible[n - 1, CarmichaelLambda[n]]; rm = 0; s={}; Do[If[!carmichaelQ[n], Continue[]]; r = DivisorSigma[1,n]/n; If[r > rm, AppendTo[s, n]; rm = r], {n, 2, 10^5}]; s
%Y A329460 Cf. A000203, A002997, A004394, A328691.
%K A329460 nonn,more
%O A329460 1,1
%A A329460 _Amiram Eldar_, Nov 13 2019