A363765 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

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 which have no common digit with 27.

a(673) can't be calculated because its neighbors would be 216, 397, and 548, and they use all digits.

CROSSREFS