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 A216722 #16 Apr 14 2021 05:28:03 %S A216722 1,0,0,1,5,0,0,0,1,18,5,0,0,0,1,95,18,6,0,0,0,1,600,84,28,7,0,0,0,1, %T A216722 4307,568,116,40,8,0,0,0,1,35168,4122,810,156,54,9,0,0,0,1,321609, %U A216722 33910,5975,1100,205,70,10,0,0,0,1 %N A216722 Triangle read by rows: number of circular permutations of [1..n] with k modular progressions of rise 1, distance 1 and length 3 (n >= 3, 0 <= k <= n). %D A216722 Wayne M. Dymacek, Isaac Lambert and Kyle Parsons, Arithmetic Progressions in Permutations, http://math.ku.edu/~ilambert/CN.pdf, 2012. %e A216722 Triangle begins: %e A216722 1, 0, 0, 1; %e A216722 5, 0, 0, 0, 1; %e A216722 18, 5, 0, 0, 0, 1; %e A216722 95, 18, 6, 0, 0, 0, 1; %e A216722 600, 84, 28, 7, 0, 0, 0, 1; %e A216722 4307, 568, 116, 40, 8, 0, 0, 0, 1; %e A216722 35168, 4122, 810, 156, 54, 9, 0, 0, 0, 1; %e A216722 321609, 33910, 5975, 1100, 205, 70, 10, 0, 0, 0, 1; %e A216722 ... %Y A216722 Columns 1..2 are A165962, A216723. %Y A216722 Row sums are A000142(n-1). %Y A216722 Cf. A216716, A216718, A216719, A165962. %K A216722 nonn,tabf %O A216722 3,5 %A A216722 _N. J. A. Sloane_, Sep 15 2012