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A275376
The even digits in the sequence appear in blocks and the successive sizes of these blocks are given by the sequence itself.
1
1, 2, 3, 4, 6, 5, 7, 8, 20, 9, 10, 22, 21, 11, 12, 24, 26, 23, 13, 14, 28, 40, 15, 16, 42, 44, 46, 17, 18, 48, 60, 62, 25, 19, 30, 64, 66, 68, 80, 82, 84, 86, 88, 200, 31, 32, 202, 204, 201, 33, 34, 206, 208, 220, 35, 36, 222, 224, 226, 228, 240, 242, 244, 37, 38, 246, 248, 260, 262, 264, 266, 203, 39, 50, 268, 280, 282, 27, 51, 52, 284, 286, 288, 205, 53, 54, 400, 402, 404, 406
OFFSET
1,2
COMMENTS
This is the lexicographically first such sequence starting with a(1)=1 and being always extended with the smallest integer not yet present that doesn't lead to a contradiction.
LINKS
EXAMPLE
The blocks of even digits are indicated here by parentheses; the successive block-sizes are 1, 2, 3, 4, 6, 5,... which reproduces the sequence itself:
1,(2),3,(4,6),5,7,(8,20),9,1(0,22,2)1,11,1(2,24,26,2)3,13,1(4,28,40),15...
CROSSREFS
Sequence in context: A269365 A269366 A361481 * A342798 A132284 A131966
KEYWORD
nonn,base
AUTHOR
STATUS
approved