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 A080641 #11 Mar 30 2012 17:27:18
%S A080641 4,6,7,10,11,15,20,21,22,25,30,31,32,33,35,36,37,38,39,40,45,50,51,52,
%T A080641 55,56,57,58,59,60,65,70,75,76,80,85,90,95,100,105,106,107,108,109,
%U A080641 110,111,112,113,114,115,120,125,126,127,130,135,140,145,150,155,156,157
%N A080641 a(1) = 4; for n>1, a(n) is taken to be the smallest integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) is divisible by 5".
%H A080641 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL6/Cloitre/cloitre2.html">Numerical analogues of Aronson's sequence</a>, J. Integer Seqs., Vol. 6 (2003), #03.2.2.
%H A080641 B. Cloitre, N. J. A. Sloane and M. J. Vandermast, <a href="http://arXiv.org/abs/math.NT/0305308">Numerical analogues of Aronson's sequence</a> (math.NT/0305308)
%H A080641 <a href="/index/Aa#aan">Index entries for sequences of the a(a(n)) = 2n family</a>
%F A080641 {a(a(n))} = {5i, i >= 2}.
%Y A080641 Cf. A080639, A080640, A079000.
%K A080641 nonn,easy
%O A080641 1,1
%A A080641 _N. J. A. Sloane_ and Benoit Cloitre, Feb 28 2003
%E A080641 More terms from _Matthew Vandermast_, Feb 28 2003