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 A379724 #25 Jan 23 2025 12:35:16
%S A379724 2,6,30,126,8190,131070,524286,2147483646,2305843009213693950,
%T A379724 618970019642690137449562110,162259276829213363391578010288126,
%U A379724 170141183460469231731687303715884105726
%N A379724 a(n) = A000668(n) - 1.
%F A379724 a(n) = A023900(A000396(n)), provided no odd perfect numbers exist.
%F A379724 Conjecture; a(n) = A072868(n) - 2. - _Omar E. Pol_, Jan 16 2025
%t A379724 nn = 12; A023900[n_] := DivisorSum[n, MoebiusMu[#] # &]; Table[A023900[PerfectNumber[n]], {n, 1, nn}]
%Y A379724 Cf. A000396, A000668, A023900, A072868, A379725.
%K A379724 nonn
%O A379724 1,1
%A A379724 _Mats Granvik_ and _Antti Karttunen_, Dec 31 2024