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A277677 Each even term "t" of the sequence is followed by t odd terms and each even digit "k" of the sequence is followed by k odd digits. 1
0, 2, 1, 3, 4, 5, 7, 9, 121, 10, 21, 123, 125, 127, 129, 141, 11, 143, 13, 145, 1110, 23, 147, 15, 149, 17, 161, 19, 31, 163, 33, 35, 165, 37, 39, 167, 51, 53, 169, 55, 57, 181, 59, 71, 73, 183, 75, 77, 79, 185, 91, 93, 95, 187, 97, 99, 111, 25, 189, 113, 115, 321, 323, 325, 327, 329, 341, 117, 27, 343, 119, 29, 345 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

After a(1) = 0, the sequence is always extended with the smallest integer not yet present which does not lead to a contradiction.

In a private mail to Eric Angelini, Lars Blomberg wrote about the b-file: "Only the even terms 0, 2, 4, 10, 1110, 12, 110, 6, 8, 2110, 2112, 2114, 14, 16, 18, 1112, 112, 2116 [are in this b-file]; so the sequence will continue from 2116 on with 2116 odd numbers, then an even one, etc."

LINKS

Lars Blomberg, Table of n, a(n) for n = 1..8887

EXAMPLE

There are respectively 0 odd terms after "0", then 2 odd terms after "2" (they are 1 and 3), then 4 odd terms after "4" (they are 5, 7, 9 and 121), then 10 odd terms after "10" (they are 221, 123, 125, 127, 129, 141, 11, 143, 13 and 145), etc.

But there are also respectively 0 odd digits after "0", then 2 odd digits after "2" (they are 1 and 3), then 4 odd digits after "4" (they are 4, 5, 7, 9 and 1), then 2 odd digits after the "2" of "121" (they are the last "1" of "121" and the starting "1" of "10"), then 0 odd digits after "0", then 2 odd digits after the "2" of "21" (they are the "1" of "21" and the starting "1" of 123), etc.

CROSSREFS

Cf. A277623.

Sequence in context: A277518 A277383 A077159 * A075379 A308000 A029636

Adjacent sequences:  A277674 A277675 A277676 * A277678 A277679 A277680

KEYWORD

nonn,base

AUTHOR

Eric Angelini and Lars Blomberg Oct 26 2016

STATUS

approved

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Last modified May 28 15:33 EDT 2020. Contains 334684 sequences. (Running on oeis4.)