A331880 Lexicographically earliest sequence of distinct positive integers such that (last digit of a(n)) > (first digit of a(n+1)).

2, 12, 13, 14, 3, 15, 4, 16, 5, 17, 6, 18, 7, 19, 8, 22, 102, 103, 23, 24, 25, 26, 27, 28, 29, 32, 104, 33, 105, 34, 35, 36, 37, 38, 39, 42, 106, 43, 107, 44, 108, 45, 46, 47, 48, 49, 52, 109, 53, 112, 113, 114, 115, 116, 54, 117, 55, 118, 56, 57, 58, 59, 62, 119, 63, 122, 123, 124, 125, 126, 127, 64, 128, 65

Offset

1,1

Comments

No integer ending in 0 or 1 is a member of the sequence.

Links

Carole Dubois, Table of n, a(n) for n = 1..14685

Example

a(1) cannot be 1 as there is no a(2) whose first digit would be 0
a(1) = 2 and 2 (the last digit) is > 1, this 1 being the first digit of a(2) = 12
a(2) = 12 and 2 (the last digit) is > 1, this 1 being the first digit of a(3) = 13
a(3) = 13 and 3 (the last digit) is > 1, this 1 being the first digit of a(4) = 14
a(4) = 14 and 4 (the last digit) is > 3, this 3 being the first digit of a(5) = 3; etc.

Crossrefs

Cf. A331879 for the variant where the last digit of a(n) is < than the first digit of a(n+1).

Sequence in context: A169900 A140355 A007041 * A028424 A037311 A031257

Adjacent sequences: A331877 A331878 A331879 * A331881 A331882 A331883

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Jan 30 2020

Status

approved