A363765 Lexicographically earliest sequence of numbers in a hexagonal spiral such that their neighbors have no common digit.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 44, 11, 20, 13, 22, 14, 23, 15, 24, 16, 25, 17, 26, 33, 27, 30, 28, 34, 55, 29, 40, 35, 60, 57, 46, 37, 18, 39, 47, 19, 36, 45, 70, 12, 48, 51, 49, 31, 50, 21, 38, 41, 53, 61, 42, 58, 32, 80, 52, 64, 59, 62, 81, 56, 43, 72

Offset

1,3

Comments

This sequence ends with 672 terms.

Links

Carole Dubois, Table of n, a(n) for n = 1..672

Carole Dubois, Hexagonal spiral for A363765

Example

a(26) = 27 because the neighbors of the 26th hexagon are 10, 30, 33, 44, 48, 51 who have no common digit with 27.
a(673) can't be calculated because its neighbors would be 216, 397 and 548 and they are using all digits.

Crossrefs

Cf. A000384, A003458, A014105, A056105.

Sequence in context: A141709 A330192 A062683 * A137857 A161980 A183533

Adjacent sequences: A363762 A363763 A363764 * A363766 A363767 A363768

Keyword

base,nonn,fini,full

Author

Carole Dubois, Jun 20 2023

Status

approved