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 A105248 #21 Jan 14 2024 13:28:19
%S A105248 1,2,1,1,2,1,3,3,1,2,3,1,3,4,4,4,4,2,3,3,4,3,2,3,2,2,3,5,5,4,3,4,2,5,
%T A105248 6,2,5,3,2,3,3,3,3,3,4,2,4,2,5,2,3,5,3,6,4,5,2,5,4,3,3,3,4,2,5,4,4,5,
%U A105248 5,4,5,1,3,6,4,2,2,4,3,4,5,7,6,5,4,8,4
%N A105248 Number of distinct prime divisors of 88...887 (with n 8's).
%H A105248 Amiram Eldar, <a href="/A105248/b105248.txt">Table of n, a(n) for n = 0..199</a>
%F A105248 a(n) = A001221(A173812(n+1)). - _Michel Marcus_, Jan 27 2014
%e A105248 The number of distinct prime divisors of 87 is 2.
%e A105248 The number of distinct prime divisors of 887 is 1 (prime).
%e A105248 The number of distinct prime divisors of 8887 is 1 (prime).
%t A105248 Table[PrimeNu[(8*10^(n + 1) - 17)/9], {n, 1, 50}] (* _G. C. Greubel_, May 21 2017 *)
%o A105248 (PARI) a(n) = omega((8*10^(n+1)-17)/9); \\ _Michel Marcus_, Jan 27 2014
%Y A105248 Cf. A104524, A104889.
%K A105248 nonn,base
%O A105248 0,2
%A A105248 _Parthasarathy Nambi_, Apr 29 2005
%E A105248 More terms from Brian Lauer (bel136(AT)psu.edu), Feb 23 2006
%E A105248 Corrected and extended by _Michel Marcus_, Jan 27 2014
%E A105248 More terms from _Amiram Eldar_, Jan 27 2020