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 A194842 #5 Mar 30 2012 18:57:44 %S A194842 1,2,3,4,5,6,8,9,10,7,12,14,15,11,13,17,19,21,16,18,20,23,25,27,22,24, %T A194842 26,28,31,33,35,29,32,34,36,30,39,42,44,37,40,43,45,38,41,48,51,54,46, %U A194842 49,52,55,47,50,53,58,61,64,56,59,62,65,57,60,63,66,70,73,76 %N A194842 Rectangular array, by antidiagonals: row n gives the positions of n in the fractal sequence A194841; an interspersion. %C A194842 See A194832 and A194841. %e A194842 Northwest corner: %e A194842 1...2...4...8...12..17..23 %e A194842 3...5...9...14..19..25..33 %e A194842 6...10..15..21..27..35..44 %e A194842 7...11..16..22..29..37..46 %e A194842 13..18..24..32..40..49..59 %t A194842 r = -Sqrt[3]; %t A194842 t[n_] := Table[FractionalPart[k*r], {k, 1, n}]; %t A194842 f = Flatten[Table[Flatten[(Position[t[n], #1] &) /@ Sort[t[n], Less]], {n, 1,20}]] (* A194841 *) %t A194842 TableForm[Table[Flatten[(Position[t[n], #1] &) /@ Sort[t[n], Less]], {n, 1, 15}]] %t A194842 row[n_] := Position[f, n]; %t A194842 u = TableForm[Table[row[n], {n, 1, 20}]] %t A194842 g[n_, k_] := Part[row[n], k]; %t A194842 p = Flatten[Table[g[k, n - k + 1], {n, 1, 13}, %t A194842 {k, 1, n}]] (* A194842 *) %t A194842 q[n_] := Position[p, n]; Flatten[ %t A194842 Table[q[n], {n, 1, 80}]] (* A194843 *) %Y A194842 Cf. A194841, A194843, A194832. %K A194842 nonn,tabl %O A194842 1,2 %A A194842 _Clark Kimberling_, Sep 04 2011