A303880 Lexicographically earliest sequence of distinct terms such that a(n) shares at least one even digit with a(n+1).

2, 12, 20, 10, 30, 40, 4, 14, 24, 21, 22, 23, 25, 26, 6, 16, 36, 46, 34, 41, 42, 27, 28, 8, 18, 38, 48, 43, 44, 45, 47, 49, 54, 64, 56, 60, 50, 70, 80, 58, 68, 61, 62, 29, 32, 52, 72, 82, 78, 81, 83, 84, 74, 94, 104, 90, 100, 101, 102, 92, 112, 120, 103, 105, 106, 63, 65, 66, 67, 69, 76

Offset

1,1

Comments

The sequence starts with a(1) = 2 and is always extended with the smallest integer not present that doesn't lead to a contradiction.

The sequence is not a permutation of the integers > 0 as no term of A014261 (Numbers that contain odd digits only) will ever show.

Links

Jean-Marc Falcoz, Table of n, a(n) for n = 1..1001

Example

a(1) = 2 shares 2 with 12;
a(2) = 12 shares 2 with 20;
a(3) = 20 shares 0 with 10;
a(4) = 10 shares 0 with 30;
a(5) = 30 shares 0 with 40;
a(6) = 40 shares 4 with 4;
a(7) = 4 shares 4 with 14;
a(8) = 14 shares 4 with 24;
etc.

Crossrefs

Cf. A303879 for the same idea with odd digits.

Sequence in context: A259409 A073257 A240905 * A174977 A011532 A277964

Adjacent sequences: A303877 A303878 A303879 * A303881 A303882 A303883

Keyword

nonn,base

Author

Eric Angelini and Jean-Marc Falcoz, May 02 2018

Status

approved