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A316765
A self-"read and extend" sequence built following the three rules given in the Comments section.
2
1, 0, 2, 6, 18, 9, 27, 13, 39, 19, 9, 4, 2, 1, 0, 0, 0, 0, 0, 0, 3, 5, 7, 8, 10, 11, 5, 2, 1, 3, 1, 12, 6, 3, 1, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14, 15, 16, 17, 20, 21, 22, 23, 24, 12, 36, 18, 9, 4, 12, 6, 3, 9, 25, 75, 37, 111, 333, 999, 499, 1497, 4491, 2245, 6735, 3367, 10101, 5050, 15150, 7575
OFFSET
1,3
COMMENTS
Start with a(1) = 1 and read the sequence digit by digit starting from the left:
when the read digit is odd, we divide by 2 the last term of the sequence, then extend the sequence with the entire part of the result;
when the read digit is even (but not 0), we multiply by 3 the last term of the sequence, then extend the sequence with the result;
when the read digit is 0, we extend the sequence with the smallest integer not yet present in the sequence.
LINKS
EXAMPLE
The odd digit 1 divides 1 by two (which is 0,5), and |0,5| is 0;
the digit 0 extends the sequence with the smallest integer not present yet in the sequence, which is 2;
the digit 2 multiplies 2 by three, which is 6;
the digit 6 multiplies 6 by three, which is 18;
the odd digit 1 divides 18 by two, which is 9;
the digit 8 multiplies 9 by three, which is 27; etc.
CROSSREFS
Cf. (for more self-"read and extend" sequences) A316749, A316750, A316758, A316764.
Sequence in context: A181490 A340210 A165325 * A097635 A151870 A045962
KEYWORD
base,nonn,look
AUTHOR
STATUS
approved