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A365986 Multiply each term by 3 and erase the leftmost digit of the result: this leaves the sequence unchanged. 2
1, 7, 9, 13, 71, 57, 119, 373, 791, 597, 1199, 3733, 7911, 12637, 70879, 90293, 63431, 54477, 118159, 706053, 1235351, 3745117, 7915039, 9305013, 13101671, 37700557, 79233519, 126411173, 375470391, 1125156797, 3708385599, 11236128533, 37078709511, 112359569837 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
This is the lexicographically earliest sequence of distinct positive terms with this property.
If the erasure of the leftmost digit leaves one or more leading zeros in the result, erase also those zeros.
LINKS
EXAMPLE
a(1) = 1 and 3*1 = 3; erasing the leftmost digit 3 leaves nothing;
a(2) = 7 and 3*7 = 21; erasing the leftmost digit 2 leaves 1;
a(3) = 9 and 3*9 = 27; erasing the leftmost digit 2 leaves 7;
a(4) = 13 and 3*13 = 39; erasing the leftmost digit 3 leaves 9;
a(5) = 71 and 3*71 = 213; erasing the leftmost digit 2 leaves 13; etc.
We see that the last column of the above table is the sequence itself.
MAPLE
a:= proc(n) option remember; `if`(n=1, 1,
(t-> parse(cat(3-irem(t, 3), t))/3)(a(n-1)))
end:
seq(a(n), n=1..35); # Alois P. Heinz, Sep 24 2023
CROSSREFS
Sequence in context: A032487 A332103 A160777 * A063189 A004472 A145827
KEYWORD
nonn,base,easy
AUTHOR
Eric Angelini, Sep 24 2023
EXTENSIONS
More terms from Alois P. Heinz, Sep 24 2023
STATUS
approved

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Last modified July 16 08:10 EDT 2024. Contains 374345 sequences. (Running on oeis4.)