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 A194966 #9 Oct 18 2021 08:45:31 %S A194966 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,18,19,20,21,17,22,25,26,27,28, %T A194966 23,24,29,33,34,35,36,30,31,32,37,42,43,44,45,38,39,40,41,46,52,53,54, %U A194966 55,47,48,49,50,51,56,63,64,65,66,57,59,60,61,62,58,67,75,76 %N A194966 Interspersion fractally induced by A194965, a rectangular array, by antidiagonals. %C A194966 See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194966 is a permutation of the positive integers, with inverse A194967. %H A194966 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %e A194966 Northwest corner: %e A194966 1...2...4...7...11..16 %e A194966 3...5...8...12..18..25 %e A194966 6...9...13..19..26..34 %e A194966 10..14..20..27..35..44 %e A194966 15..21..28..36..45..55 %t A194966 p[n_] := Floor[(n + 4)/5] + Mod[n - 1, 5] %t A194966 Table[p[n], {n, 1, 90}] (* A053824(n+5), n>=0 *) %t A194966 g[1] = {1}; g[n_] := Insert[g[n - 1], n, p[n]] %t A194966 f[1] = g[1]; f[n_] := Join[f[n - 1], g[n]] %t A194966 f[20] (* A194965 *) %t A194966 row[n_] := Position[f[30], n]; %t A194966 u = TableForm[Table[row[n], {n, 1, 5}]] %t A194966 v[n_, k_] := Part[row[n], k]; %t A194966 w = Flatten[Table[v[k, n - k + 1], {n, 1, 13}, %t A194966 {k, 1, n}]] (* A194966 *) %t A194966 q[n_] := Position[w, n]; Flatten[ %t A194966 Table[q[n], {n, 1, 80}]] (* A194967 *) %Y A194966 Cf. A194959, A194965, A194967 (inverse). %K A194966 nonn,tabl %O A194966 1,2 %A A194966 _Clark Kimberling_, Sep 07 2011