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 A071571 #32 Jan 25 2025 03:10:45
%S A071571 1,2,4,8,6,32,64,12,256,512,24,2048,36,30,16384,32768,96,72,262144,
%T A071571 192,1048576,2097152,60,8388608,216,768,67108864,288,1536,536870912,
%U A071571 1073741824,120,576,8589934592,6144,34359738368,68719476736,180,864
%N A071571 Smallest number whose square has exactly 2n+1 divisors.
%C A071571 Only squares have an odd number of divisors.
%H A071571 Amiram Eldar, <a href="/A071571/b071571.txt">Table of n, a(n) for n = 0..3325</a>
%F A071571 a(n) <= 2^n, where the equality holds if and only if n=0 or 2n+1 is prime. - _Jianing Song_, Aug 30 2021
%e A071571 a(4)=6 because it is the smallest number followed by 10,14,15,16,21,22,... whose squares have 2*4 + 1, i.e., 9 divisors.
%o A071571 (PARI) a(n) = {k = 1; while (numdiv(k^2) != (2*n+1), k++); return (k);} \\ _Michel Marcus_, Jul 27 2013
%Y A071571 Cf. A005179.
%Y A071571 Identical to A016017 shifted left.
%K A071571 nonn
%O A071571 0,2
%A A071571 _Lekraj Beedassy_, May 31 2002
%E A071571 More terms from _Vladeta Jovovic_, Jun 05 2002
%E A071571 a(0) prepended by _Jianing Song_, Aug 30 2021