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 A192088 #8 Mar 31 2012 10:29:58 %S A192088 2,6,24,114,528,2334,9528,36834,135918,484206,1678152,5694786, %T A192088 19007808,62625054,204215340,660445914,2121665016,6778399914, %U A192088 21557206332,68294432778,215651021484,679023425238,2132750062560,6684084844362,20907052386534,65279503654446 %N A192088 Number of permutations of [n] realized by the shift on 3 letters. %D A192088 S. Elizalde, The number of permutations realized by a shift, SIAM J. Discrete Math. 23 (2009), 765--786. %H A192088 Sergi Elizalde, <a href="http://arxiv.org/abs/0909.2274">The number of permutations realized by a shift</a>, arXiv:0909.2274v1 [math.CO] %F A192088 a(n)=3^(n-2)+sum(psi_3(t)*3^(n-t-1),t=1..n-1)-(n-1)*sum(psi_2(t)*2^(n-t-1),t=0..n-1), where psi_N(t) is the number of primitive words of length t over an N-letter alphabet, expressible in terms of the Möbius function. %Y A192088 Cf. A059413. %K A192088 nonn %O A192088 2,1 %A A192088 _Sergi Elizalde_, Jun 23 2011