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 A105555 #14 May 25 2017 10:34:39 %S A105555 2,3,3,5,3,7,3,7,5,7,3,13,3,7,7,11,3,13,3,13,7,7,3,19,5,7,7,13,3,19,3, %T A105555 13,7,7,7,23,3,7,7,19,3,19,3,13,13,7,3,29,5,13,7,13,3,19,7,19,7,7,3, %U A105555 37,3,7,13,17,7,19,3,13,7,19,3,37,3,7,13,13,7,19,3,29,11,7,3,37,7,7,7,19,3 %N A105555 Let d = number of divisors of n; a(n) = d-th prime. %H A105555 Antti Karttunen, <a href="/A105555/b105555.txt">Table of n, a(n) for n = 1..10000</a> %F A105555 a(n) = A000040(A000005(n)). - _Antti Karttunen_, May 25 2017 %e A105555 n = 6 has 4 divisors, prime(4) = 7, so a(6) = 7. %t A105555 Prime[DivisorSigma[0,Range[90]]] (* _Harvey P. Dale_, Jul 27 2011 *) %o A105555 (PARI) d(n) = for(x=1,n,print1(prime(numdiv(x))",")) %o A105555 (Python) %o A105555 from sympy import prime, divisor_count %o A105555 def a(n): return prime(divisor_count(n)) # _Indranil Ghosh_, May 25 2017 %Y A105555 Cf. A000005, A000040, A105560, A105561. %K A105555 easy,nonn %O A105555 1,1 %A A105555 _Cino Hilliard_, May 03 2005