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 A080086 #10 Jan 15 2015 16:22:11
%S A080086 0,1,1,2,4,5,6,8,9,13,14,17,18,19,21,23,27,28,31,32,34,36,40,42,46,48,
%T A080086 49,50,53,54,61,62,66,67,71,72,75,80,81,84,86,88,93,94,95,97,102,108,
%U A080086 110,111,112,115,116,123,126,129,131,134,136,138,139,143,151,152,153
%N A080086 Number of factors of 3 in the factorial of the n-th prime, counted with multiplicity.
%F A080086 a(n) = sum_{k=1..L} floor(prime(n) / 3^k), where L = log(p_n)/log(3).
%t A080086 lst={};Do[p=Prime[n];s=0;While[p>1,p=IntegerPart[p/3];s+=p;];AppendTo[lst,s],{n,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Jul 28 2009 *)
%t A080086 Join[{0},FactorInteger[#][[2,2]]&/@(Prime[Range[2,70]]!)] (* _Harvey P. Dale_, Sep 05 2014 *)
%Y A080086 Cf. A080084, A080085, A080087.
%K A080086 nonn
%O A080086 1,4
%A A080086 _Paul D. Hanna_, Jan 26 2003