

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
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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(3irem(t, 3), t))/3)(a(n1)))
end:


CROSSREFS



KEYWORD

nonn,base,easy


AUTHOR



EXTENSIONS



STATUS

approved



