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 A209351 #6 Mar 30 2012 17:37:37
%S A209351 1,1,11,182,3542,76258,1753522,42269392,1055518634,27091380674,
%T A209351 710781384782,18986685114964,514838929566304,14138508923416768,
%U A209351 392518929926801888,11000540560168582016,310851652685562860378,8848249504532000817058,253498769515046174725606
%N A209351 Number of initially rising meander words, where each letter of the cyclic 5-ary alphabet occurs n times.
%C A209351 In a meander word letters of neighboring positions have to be neighbors in the alphabet, where in a cyclic alphabet the first and the last letters are considered neighbors too. The words are not considered cyclic here.
%C A209351 A word is initially rising if it is empty or if it begins with the first letter of the alphabet that can only be followed by the second letter in this word position.
%C A209351 a(n) is also the number of (5*n-1)-step walks on 5-dimensional cubic lattice from (1,0,...,0) to (n,n,...,n) with positive unit steps in all dimensions such that the indices of dimensions used in consecutive steps differ by 1 or are in the set {1,5}.
%e A209351 a(0) = 1: the empty word.
%e A209351 a(1) = 1 = |{abcde}|.
%e A209351 a(2) = 11 = |{abaedcbcde, abaededcbc, abcbaedcde, abcbaededc, abcbcdeaed, abcbcdedea, abcdcbaede, abcdeabcde, abcdeaedcb, abcdedcbae, abcdedeabc}|.
%Y A209351 Column k=5 of A209349.
%K A209351 nonn,walk
%O A209351 0,3
%A A209351 _Alois P. Heinz_, Mar 06 2012