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 A088818 #11 Jul 24 2024 21:32:20
%S A088818 6,16,28,32,64,128,256,496,512,1024,1952,2048,4096,8128,8192,16384,
%T A088818 32768,32896,65536,130304,131072,262144,522752,524288,1048576,2097152,
%U A088818 4194304,8382464,8388608,16777216,33550336,33554432,67108864,134193152,134217728,268435456
%N A088818 Numbers k whose abundance-radius does not exceed log(log(k)), i.e., abs(sigma(k)-2*k) <= log(log(k)).
%e A088818 The perfect numbers are all terms.
%e A088818 It is an infinite sequence since it includes all the powers of 2 (A000079) that are larger than 8 (as almost-perfect numbers).
%t A088818 abu[x_] := Abs[DivisorSigma[1, x]-2*x]; Do[If[ !Greater[abu[n], Log[Log[n]]//N], Print[n]], {n, 1, 1000000}]
%o A088818 (PARI) is(n) = n > 1 && abs(sigma(n)-2*n) < log(log(n)); \\ _Amiram Eldar_, Jul 24 2024
%Y A088818 Cf. A033880, A088009, A088010, A088011, A088012, A077374, A000396, A000079.
%K A088818 nonn
%O A088818 1,1
%A A088818 _Labos Elemer_, Oct 20 2003
%E A088818 a(28)-a(34) from _Donovan Johnson_, Dec 21 2008
%E A088818 a(35)-a(36) from _Amiram Eldar_, Jul 24 2024