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 A354073 #17 May 12 2024 00:45:23 %S A354073 1,6,28,120,496,672,30240,32760,523776,2178540,23569920,33550336, %T A354073 45532800,142990848,459818240,1379454720,1476304896,8589869056, %U A354073 14182439040,31998395520,43861478400,51001180160,66433720320,137438691328,153003540480,403031236608,518666803200 %N A354073 Multiply-perfect numbers that are the sum of the divisors of some number. %C A354073 Conjecture: 8128 is only multiply-perfect number that is not in this sequence. %C A354073 The distinct values of A000203(A066961(n)). %H A354073 Amiram Eldar, <a href="/A354073/b354073.txt">Table of n, a(n) for n = 1..50</a> %e A354073 The multiply-perfect number 28 is in the sequence because 28 = sigma(12). %o A354073 (Magma) Set(Sort([&+Divisors(m): m in [1..10^7] | IsIntegral(&+Divisors(&+Divisors(m)) / &+Divisors(m))])) %Y A354073 Intersection of A007691 and A002191. %Y A354073 Cf. A000203, A066961, A354072, A354074. %K A354073 nonn %O A354073 1,2 %A A354073 _Jaroslav Krizek_, May 16 2022 %E A354073 a(18)-a(27) from _Amiram Eldar_, May 12 2024