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 A175906 #4 Aug 10 2024 15:18:24 %S A175906 12,10924032,16125952,3757637632,45091651584,66563866624, %T A175906 727145809044307968,1152771972099211264, %U A175906 845044701535107443245558061611352064 %N A175906 Numbers n of the form 2^(A000043-1)*A046528 such that sigma(n) is a perfect number. %C A175906 sigma(sigma(A046528(2,12,13,18,21,22,56,57,175,176,177,..))) is Mersenne prime. %F A175906 a(n)= 2^( A000043(2,5,5,6,7,7,8,8,9,9,9,..)-1)*A046528(2,12,13,18,21,22,56,57,175,176,177,..). %e A175906 45091651584=2^18*3*7*8191, sigma(45091651584)=137438691328 is perfect number. %Y A175906 Cf. A000396, A000203, A000668, A000043, A046528, A063103. %K A175906 nonn %O A175906 1,1 %A A175906 _Manuel Valdivia_, Oct 12 2010