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A363765
Lexicographically earliest sequence of numbers in a hexagonal spiral such that their neighbors have no common digit.
2
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.
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
KEYWORD
base,nonn,fini,full
AUTHOR
Carole Dubois, Jun 20 2023
STATUS
approved