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 A223609 #18 Sep 08 2022 08:46:04 %S A223609 40,1696,518656,34358296576 %N A223609 Numbers n whose abundance is 10. Sigma(n)-2*n = 10. %C A223609 Suggested by _N. J. A. Sloane_ and _Robert G. Wilson v_. %C A223609 a(5) > 10^12. %C A223609 a(5) > 10^13. - _Giovanni Resta_, Mar 29 2013 %C A223609 a(5) > 10^18. - _Hiroaki Yamanouchi_, Aug 23 2018 %C A223609 Any term x of this sequence can be combined with any term y of A101223 to satisfy the property (sigma(x)+sigma(y))/(x+y) = 2, which is a necessary (but not sufficient) condition for two numbers to be amicable. - _Timothy L. Tiffin_, Sep 13 2016 %e A223609 n = 34358296576. sigma(n)-2*n = 10. %t A223609 Select[Range[1, 10^8], DivisorSigma[1, #] - 2 # == 10 &] (* _Vincenzo Librandi_, Sep 15 2016 *) %o A223609 (PARI) for(n=1, 10^8, if(sigma(n)-2*n==10, print1(n ", "))) %o A223609 (Magma) [n: n in [1..9*10^6] | (SumOfDivisors(n)-2*n) eq 10]; // _Vincenzo Librandi_, Sep 15 2016 %Y A223609 Cf. A000203, A033880, A101223 (deficiency 10). %K A223609 nonn,more %O A223609 1,1 %A A223609 _Donovan Johnson_, Mar 23 2013