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 A066464 #10 Jun 22 2025 05:35:08
%S A066464 1,3,5,7,13,17,32,38,85,67,162,137,338,203,760,247,1225,472,578,682,
%T A066464 1012,787,9112,1463,2048,2047,2888,2363,5513,3465,5512,6682,8978,5197,
%U A066464 17672,5198,71442,9653,29768,8662,40898,13513,81608,15593,131072,35437
%N A066464 Least number k such that k has n anti-divisors.
%C A066464 See A066272 for definition of anti-divisor.
%H A066464 Donovan Johnson, <a href="/A066464/b066464.txt">Table of n, a(n) for n = 0..400</a>
%t A066464 antid[n_] := Select[ Union[ Join[ Select[ Divisors[2n - 1], OddQ[ # ] && # != 1 & ], Select[ Divisors[2n + 1], OddQ[ # ] && # != 1 & ], 2n/Select[ Divisors[ 2n], OddQ[ # ] && # != 1 &]]], # < n & ]; a = Table[0, {50} ]; Do[ b = Length[ antid[n]]; If[ b < Length[a] && a[[b + 1]] == 0, a[[b + 1]] = n], {n, 1, 2^17} ]; a
%Y A066464 Cf. A066272.
%K A066464 nonn
%O A066464 0,2
%A A066464 _Robert G. Wilson v_, Jan 02 2002