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A275659
The nonprime digits in the sequence appear in blocks and the successive sizes of these blocks are given by the sequence itself.
2
1, 2, 3, 4, 6, 5, 7, 8, 9, 12, 10, 11, 20, 14, 16, 13, 18, 19, 15, 21, 40, 41, 44, 22, 23, 24, 46, 48, 49, 17, 25, 26, 60, 61, 64, 66, 27, 28, 68, 69, 80, 81, 84, 42, 29, 86, 88, 89, 90, 43, 30, 91, 94, 96, 98, 99, 31, 100, 101, 104, 106, 108, 109, 45, 32, 33, 34, 110, 111, 114, 116, 47, 35, 36, 118, 119, 140, 141, 144, 37, 38, 146
OFFSET
1,2
COMMENTS
The sequence is started with a(1)=1 and always extended with the smallest integer not yet present that does not lead to a contradiction.
LINKS
EXAMPLE
The blocks of nonprime digits are indicated hereunder 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,(8,9,1)2,(10,11),2(0,14,16,1)3,(18,19,1)5,...
CROSSREFS
Sequence in context: A073284 A057511 A121730 * A244321 A364824 A062894
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Lars Blomberg, Aug 04 2016
STATUS
approved