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 A194865 #8 Jul 30 2023 03:35:45 %S A194865 1,1,2,1,2,3,4,1,2,3,4,1,5,2,3,4,1,5,2,6,3,4,1,5,2,6,3,7,4,8,1,5,2,6, %T A194865 3,7,4,8,1,5,9,2,6,3,7,4,8,1,5,9,2,6,10,3,7,11,4,8,1,5,9,2,6,10,3,7, %U A194865 11,4,8,1,12,5,9,2,6,10,3,7,11,4,8,1,12,5,9,2,13,6,10,3,7,11,4,8 %N A194865 Triangular array (and fractal sequence): row n is the permutation of (1,2,...,n) obtained from the increasing ordering of fractional parts {-e}, {-2e}, ..., {-ne}. %C A194865 See A194832 for a general discussion. %e A194865 First nine rows: %e A194865 1 %e A194865 1 2 %e A194865 1 2 3 %e A194865 4 1 2 3 %e A194865 4 1 5 2 3 %e A194865 4 1 5 2 6 3 %e A194865 4 1 5 2 6 3 7 %e A194865 4 8 1 5 2 6 3 7 %e A194865 4 8 1 5 9 2 6 3 7 %t A194865 r = -E; %t A194865 t[n_] := Table[FractionalPart[k*r], {k, 1, n}]; %t A194865 f = Flatten[Table[Flatten[(Position[t[n], #1] &) /@ %t A194865 Sort[t[n], Less]], {n, 1, 20}]] (* A194865 *) %t A194865 TableForm[Table[Flatten[(Position[t[n], #1] &) /@ %t A194865 Sort[t[n], Less]], {n, 1, 15}]] %t A194865 row[n_] := Position[f, n]; %t A194865 u = TableForm[Table[row[n], {n, 1, 20}]] %t A194865 g[n_, k_] := Part[row[n], k]; %t A194865 p = Flatten[Table[g[k, n - k + 1], {n, 1, 13}, %t A194865 {k, 1, n}]] (* A194866 *) %t A194865 q[n_] := Position[p, n]; Flatten[Table[q[n], %t A194865 {n, 1, 80}]] (* A194864 *) %Y A194865 Cf. A194832, A194864, A194866. %K A194865 nonn,tabl %O A194865 1,3 %A A194865 _Clark Kimberling_, Sep 04 2011