A194988 Interspersion fractally induced by A194987, a rectangular array, by antidiagonals.

1, 3, 2, 6, 4, 5, 10, 7, 9, 8, 15, 11, 14, 12, 13, 21, 16, 20, 17, 19, 18, 28, 22, 27, 23, 26, 25, 24, 36, 29, 35, 30, 34, 33, 31, 32, 45, 37, 44, 38, 43, 42, 39, 41, 40, 55, 46, 54, 47, 53, 52, 48, 51, 49, 50, 66, 56, 65, 57, 64, 63, 58, 62, 59, 61, 60, 78, 67, 77

Offset

1,2

Comments

See A194959 for a discussion of fractalization and the interspersion fractally induced by a sequence. Every pair of rows eventually intersperse. As a sequence, A194988 is a permutation of the positive integers, with inverse A194989.

Links

Table of n, a(n) for n=1..69.

Index entries for sequences that are permutations of the natural numbers

Example

Northwest corner:
1...3...6...10..15..21
2...4...7...11..16..22
5...9...14..20..27..35
8...12..17..23..30..38
13..19..26..34..43..53

Mathematica

r = Sqrt[6]; p[n_] := 1 + Floor[n/r]
Table[p[n], {n, 1, 90}] (* A194986 *)
g[1] = {1}; g[n_] := Insert[g[n - 1], n, p[n]]
f[1] = g[1]; f[n_] := Join[f[n - 1], g[n]]
f[20] (* A194987 *)
row[n_] := Position[f[30], n];
u = TableForm[Table[row[n], {n, 1, 5}]]
v[n_, k_] := Part[row[n], k];
w = Flatten[Table[v[k, n - k + 1], {n, 1, 13},
{k, 1, n}]] (* A194988 *)
q[n_] := Position[w, n]; Flatten[Table[q[n],
{n, 1, 80}]]  (* A194989 *)

Crossrefs

Cf. A194959, A194986, A194988, A194989.

Sequence in context: A195114 A059399 A194984 * A195074 A194918 A194915

Adjacent sequences: A194985 A194986 A194987 * A194989 A194990 A194991

Keyword

nonn,tabl

Author

Clark Kimberling, Sep 07 2011

Status

approved