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 A090387 #19 Jun 20 2022 14:45:24 %S A090387 1,1,2,3,2,2,2,1,1,2,2,1,2,2,4,5,2,1,2,3,4,2,2,1,3,2,4,3,2,4,2,3,4,2, %T A090387 4,1,2,2,4,1,2,4,2,3,2,2,2,5,3,3,4,3,2,4,4,1,4,2,2,1,2,2,2,7,4,4,2,3, %U A090387 4,4,2,1,2,2,2,3,4,4,2,1,5,2,2,1,4,2,4,1,2,2,4,3,4,2,4,1,2,3,2,9,2,4,2,1,8 %N A090387 Numerator of d(n)/n, where d(n) (A000005) is the number of divisors of n. %C A090387 Values of n at which k first occurs, for k >= 1: 1, 3, 4, 15, 16, 175, 64, 105, 100, 567, 1024, 1925, 4096, 3645, 784, 945, 65536, ... - _Robert G. Wilson v_, Feb 04 2004. [Is this A136641? - Editors] %H A090387 Antti Karttunen, <a href="/A090387/b090387.txt">Table of n, a(n) for n = 1..65537</a> %e A090387 a(6)=2 because the number of divisors of 6 is 4 and 4 divided by 6 equals 2/3, which has 2 as its numerator. %p A090387 with(numtheory): seq(numer(tau(n)/n), n=1..105) ; # _Zerinvary Lajos_, Jun 04 2008 %o A090387 (PARI) A090387(n) = numerator(numdiv(n)/n); \\ _Antti Karttunen_, Sep 25 2018 %o A090387 (Python) %o A090387 from math import gcd %o A090387 from sympy import divisor_count %o A090387 def A090387(n): return (d := divisor_count(n))//gcd(n,d) # _Chai Wah Wu_, Jun 20 2022 %Y A090387 Cf. A000005, A090395 (denominators), A136641. %K A090387 easy,frac,nonn %O A090387 1,3 %A A090387 Ivan_E_Mayle(AT)a_provider.com, Jan 31 2004 %E A090387 More terms from _Robert G. Wilson v_, Feb 04 2004