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 A144952 #6 Mar 30 2012 17:25:51 %S A144952 0,1,5,16,44,111,268,627,1439,3250,7259,16050,35219,76730,166229, %T A144952 358180,768416,1641555,3494596,7414203,15685328,33091399,69647978, %U A144952 146250009,306490602,641044849,1338507476,2790140995,5807567462,12070739253,25056394988,51946330763,107573145767 %N A144952 Total walk count of molecular graphs for linear alkanes with n carbon atoms. %C A144952 a(n) = Sum(A198335(n,k),k=1..n-1). %C A144952 a(n) is 1/2 of the number of walks of length <= n-1 in the path graph on n vertices. Example: a(3)=5 because in the path a - b - c we have 4 walks of length 1 (ab, bc, ba, cb) and 6 walks of length 2 (aba, abc, bab, bcb, cbc, cba). %C A144952 See Table 1 on page 101 for details. %D A144952 Gerta Rucker and Christoph Rucker, "Walk counts, Labyrinthicity and complexity of acyclic and cyclic graphs and molecules", J. Chem. Inf. Comput. Sci., 40 (2000), 99-106. %e A144952 The total walk count for decane (n=10) is 3250. %p A144952 with(GraphTheory): T := proc (n, k) local G, A, B: G := PathGraph(n): A := AdjacencyMatrix(G): B := A^k: if k < n then (1/2)*add(add(B[i, j], i = 1 .. n), j = 1 .. n) else 0 end if end proc: 0, seq(add(T(n, k), k = 1 .. n-1), n = 2 .. 33); %Y A144952 Cf. A198335. %K A144952 nonn %O A144952 1,3 %A A144952 _Parthasarathy Nambi_, Sep 26 2008