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 A340568 #14 Jan 11 2021 23:17:17 %S A340568 0,0,0,1,4,10,28,61,152,318,748,1538,3496,7124,15832,32093,70192, %T A340568 141814,306508,617878,1323272,2663340,5662600,11383986,24061264, %U A340568 48330540,101653368,204049636,427414672,857503784,1789891888,3589478621,7469802592,14974962854,31081371148 %N A340568 Total number of consecutive triples matching the pattern 132 in all faro permutations of length n. %C A340568 Faro permutations are permutations avoiding the three consecutive patterns 231, 321 and 312. They are obtained by a perfect faro shuffle of two nondecreasing words of lengths differing by at most one. Also the popularity of consecutive pattern 213. %H A340568 Jean-Luc Baril, Alexander Burstein, and Sergey Kirgizov, <a href="https://arxiv.org/abs/2010.06270">Pattern statistics in faro words and permutations</a>, arXiv:2010.06270 [math.CO], 2020. See Table 1. %F A340568 G.f.: x*(-1+4*x^2+2*x+(1-2*x)*sqrt(1-4*x^2)) / ((1-2*x)*(1+sqrt(1-4*x^2))*sqrt(1-4*x^2)). %e A340568 For n = 4, there are 6 faro permutations: 1234, 1243, 1324, 2134, 2143, 3142. They contain in total 4 consecutive patterns 132 and also 4 consecutive patterns 213. %o A340568 (PARI) seq(n)={my(t=sqrt(1-4*x^2+O(x^n))); Vec(x*(-1+4*x^2+2*x+(1-2*x)*t) / ((1-2*x)*(1+t)*t), -(1+n))} \\ _Andrew Howroyd_, Jan 11 2021 %Y A340568 A001405 counts faro permutations of length n. %Y A340568 Cf. A107373, A340567, A340569. %K A340568 nonn %O A340568 0,5 %A A340568 _Sergey Kirgizov_, Jan 11 2021