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A158929 a(n) is the smallest integer not yet in the sequence with no common base-4 digit with a(n-1). 2
1, 2, 3, 4, 10, 5, 8, 7, 32, 13, 34, 15, 6, 12, 9, 48, 21, 11, 16, 14, 17, 42, 19, 170, 20, 43, 64, 46, 65, 47, 68, 58, 69, 59, 80, 62, 81, 63, 18, 255, 22, 51, 25, 60, 26, 192, 37, 195, 38, 204, 41, 207, 85, 35, 341, 40, 23, 128, 29, 130, 31, 136, 53, 138, 55, 160, 61, 162 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers of A031945 do not appear in this sequence.

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

The fifth term cannot be 5(base10)=11(base4), 6(base10)=12(base4), 7(base10)=13(base4), 8(base10)=20(base4) or 9(base10)=21(base4) because each of them has either a 0 or a 1 in its base-4 representation, which it would have in common with 4(base10)=10(base4). So a(5)=10(base10)=22(base4) which displays only digits of 2 in base 4.

CROSSREFS

Cf. A067581 (base-10), A158928 (base-3), A158930 (base-5).

Sequence in context: A286709 A082865 A265348 * A255479 A256618 A140598

Adjacent sequences:  A158926 A158927 A158928 * A158930 A158931 A158932

KEYWORD

base,easy,nonn

AUTHOR

R. J. Mathar, Mar 31 2009

STATUS

approved

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Last modified December 6 12:56 EST 2021. Contains 349563 sequences. (Running on oeis4.)