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 A105267 #10 May 13 2020 07:04:14 %S A105267 1,2,2,2,2,2,2,2,4,4,4,8,8,16,4,4,8,2,8,24,8,4,16,8,8,4,16,8,8,6,8,16, %T A105267 64,4,4,8,8,16,16,2,8,8,64,64,8,4,8,32,8,2,8,8,16,64,8,8,32,8,32,2,8, %U A105267 64,32,16,8,32,8,8,32,16,64,64,8,64,4,4,16,2 %N A105267 a(n) = the number of divisors of 33...31, with n 3s. %C A105267 The first seven 33...31 numbers are prime, so those terms are 2. - _Don Reble_, Oct 26 2006 %H A105267 Amiram Eldar, <a href="/A105267/b105267.txt">Table of n, a(n) for n = 0..203</a> %F A105267 a(n) = A000005(A033175(n)). - _Amiram Eldar_, May 13 2020 %t A105267 a[n_] := DivisorSigma[0, (10^(n + 1) - 7)/3]; Array[a, 30, 0] (* _Amiram Eldar_, May 13 2020 *) %o A105267 (PARI) a(n) = numdiv((10^(n + 1) - 7)/3); \\ _Michel Marcus_, May 13 2020 %Y A105267 Cf. A000005, A051200, A033175, A104484. %K A105267 nonn %O A105267 0,2 %A A105267 _Parthasarathy Nambi_, Apr 29 2005 %E A105267 More terms from _Don Reble_, Oct 26 2006