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 A084293 #12 Oct 15 2013 22:32:01 %S A084293 436,305635361,110,35,195566,77,26,55,38,76,938,104,212308,85,74, %T A084293 106677,86,161 %N A084293 a(n) = 2n + A054905(n). %C A084293 The sequence begins 436, 305635361, 110, 35, 195566, 77, 26, 55, 38, 76, 938, 104, 212308, 85, 74, 106677, 86, 161, ?, 91, 87, 92, 122, 111, 1585396, 145, 94, 76627, 10283, 159, 772, 133, 122, 412, 194, 142, 964, 205, 374, 925, 6725, 209, ?, 1015, 178, ?, ?, 206, 146, ?, ..., where the other missing terms (designated by "?") are unknown, if they exist (see also A206768). %F A084293 Composite x satisfying sigma(x-2n) = sigma(x) - 2n. %e A084293 To terms of A054905, where sigma(x+2n)=sigma(x)+2n replacing x+2n=y,x=y-2n, we get sigma(y)-2n=sigma(y-2n); %e A084293 For several analogous sequences, the corresponding "mirror-solutions" can be easily constructed. See: e.g. A015913-A015918; A050507, A054799, A054903-A054906; A054982-A054987; A059118; A055009, A055458, A063500, etc. %Y A084293 Cf. A054905. %K A084293 nonn,more %O A084293 1,1 %A A084293 _Labos Elemer_, May 26 2003