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 A269123 #7 Mar 02 2016 21:21:13 %S A269123 1,119,102011,117392909,142951955371,173996758190594, %T A269123 208728647384065181,246211478304046636024,285867869484243410805931, %U A269123 327305762373962750213344469,370243779118368267931211789686,414473407439255725429093382135614,459837370068489293091980501717140861 %N A269123 Number of sequences with n copies each of 1,2,...,5 avoiding the pattern 12...5. %H A269123 Alois P. Heinz, <a href="/A269123/b269123.txt">Table of n, a(n) for n = 0..150</a> %F A269123 a(n) = A008978(n) - A268841(n). %Y A269123 Row n=5 of A269129. %Y A269123 Cf. A008978, A268841. %K A269123 nonn %O A269123 0,2 %A A269123 _Alois P. Heinz_, Feb 19 2016