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 A329884 #11 Apr 14 2023 03:47:41 %S A329884 24,48,56,112,192,248,252,328,448,496,768,1016,1792,1984,2032,3240, %T A329884 6462,7936,8128,11616,11808,17412,20538,32512,49152,65528,114688, %U A329884 131056,507904,524224,786432,1048568,1835008,2080768,2096896,2097136,3145728,4194296,7340032 %N A329884 Nonunitary superperfect numbers: numbers k such that nusigma(nusigma(k)) = k, where nusigma(k) = sigma(k) - usigma(k) is the sum of nonunitary divisors of k (A048146). %C A329884 Analogous to superperfect numbers (A019279) as nonunitary perfect numbers (A064591) is analogous to perfect numbers (A000396). %H A329884 Amiram Eldar, <a href="/A329884/b329884.txt">Table of n, a(n) for n = 1..53</a> (terms below 10^10) %t A329884 usigma[1] = 1; usigma[n_] := Times @@ (1 + Power @@@ FactorInteger[n]); nusigma[n_] := DivisorSigma[1, n] - usigma[n]; Select[Range[10^6], nusigma[nusigma[#]] == # &] %Y A329884 Cf. A000396, A019279, A034448, A038843, A048146, A064591, A329881. %K A329884 nonn %O A329884 1,1 %A A329884 _Amiram Eldar_, Nov 23 2019