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 A095686 #18 Jun 06 2025 00:37:56
%S A095686 1,1,1,2,1,2,2,1,3,1,2,2,1,3,1,3,2,2,1,4,2,2,3,1,4,1,3,2,2,2,1,2,2,4,
%T A095686 1,4,1,3,3,2,1,5,3,2,3,1,4,2,4,2,2,1,6,1,2,3,2,4,1,3,2,4,1,6,1,2,3,3,
%U A095686 2,4,1,5,2,1,6,2,2,2,4,1,6,2,3,2,2,2,6,1,3,3,1,4,1,4,4,2,1,6,1,4,2,5,1,4,2
%N A095686 Half the number of divisors of nonsquares (A000037).
%C A095686 The first occurrence of n in the sequence corresponds to the nonsquare = A003680(n) = A005179(2n).
%C A095686 Also number of unordered divisor pairs (d,n/d) for n=A000037. - _Lekraj Beedassy_, Jul 30 2004
%H A095686 Amiram Eldar, <a href="/A095686/b095686.txt">Table of n, a(n) for n = 1..10000</a>
%F A095686 a(n)=A000005(A000037(n))/2.
%t A095686 m=11; DivisorSigma[0, Complement[Range[m^2], Range[m]^2]]/2 (* _Amiram Eldar_, Nov 05 2019 *)
%o A095686 (PARI) lista(nn) = {for (i = 1, nn, if (! issquare(i), print1(numdiv(i)/2, ", ")););} \\ _Michel Marcus_, Jul 27 2013
%o A095686 (Python)
%o A095686 from math import isqrt
%o A095686 from sympy import divisor_count
%o A095686 def A095686(n): return divisor_count(n+(k:=isqrt(n))+int(n>k*(k+1)))>>1 # _Chai Wah Wu_, Jun 05 2025
%K A095686 nonn
%O A095686 1,4
%A A095686 _Lekraj Beedassy_, Jul 05 2004
%E A095686 Corrected and extended by _Ray Chandler_, Jul 09 2004