login
A337368
Spiral on a 2D square lattice, one term per cell, starting at the origin with 0; the four integers forming any 2 X 2 square have all digits 0 through 9 (with duplicate digits allowed).
7
0, 1, 2, 3456789, 3, 12, 4, 356789, 24, 5, 306789, 45, 6, 103789, 7, 102, 8, 45679, 80, 35679, 9, 1028, 10, 11, 306798, 13, 42, 14, 20, 13789, 15, 204, 25, 46, 3589, 467, 16, 20359, 17, 23, 41, 208, 18, 34567, 19, 34576, 289, 54, 21, 22, 4056789, 26, 305789, 36, 145, 206, 27, 3489, 67, 1389, 70, 112, 30
OFFSET
1,3
COMMENTS
This is defined to be the lexicographically earliest permutation of the nonnegative integers with this property.
LINKS
EXAMPLE
The spiral starts with the 2 X 2 square 0,1,2,A and this square contains all the digits 0 through 9 at least once; the upper right 2 X 2 square (here) has the same property —— and so have all the 2 X 2 squares of the grid.
.
18———K——19———L——289—54———21——22 A = 3456789
| | B = 356789
208 9———G——10——11———H———13 4056789 C = 306789
| | | | D = 103789
41 F 4———B——24———5 42 26 E = 45679
| | | | | | F = 35679
23 80 12 0———1 C 14 305789 G = 1028
| | | | | | | H = 306798
17 E 3———A———2 45 20 36 I = 3589
| | | | . J = 20359
J 8——102——7———D———6 13789 . K = 34567
| | . L= 34576
16——467——I——46——25——204——15 . ...
CROSSREFS
Sequence in context: A283072 A214599 A071066 * A137601 A232962 A158347
KEYWORD
base,nonn
AUTHOR
STATUS
approved