OFFSET
1,2
COMMENTS
This is the lexicographically earliest sequence of distinct positive terms with this property.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = ceiling(a(n-1)/3*10), starting a(1) = 1. - Alois P. Heinz, Sep 24 2023
EXAMPLE
a(1) = 1 and 3*1 = 3; erasing the rightmost digit 3 leaves nothing;
a(2) = 4 and 3*4 = 12; erasing the rightmost digit 2 leaves 1;
a(3) = 14 and 3*14 = 42; erasing the rightmost digit 2 leaves 4;
a(4) = 47 and 3*47 = 141; erasing the rightmost digit 1 leaves 14;
a(5) = 157 and 3*157 = 471; erasing the rightmost digit 1 leaves 47; 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, ceil(a(n-1)/3*10)) end:
seq(a(n), n=1..30); # Alois P. Heinz, Sep 24 2023
MATHEMATICA
NestList[Ceiling[#/3*10] &, 1, 26] (* Michael De Vlieger, Sep 24 2023 *)
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Eric Angelini, Sep 24 2023
EXTENSIONS
More terms from Alois P. Heinz, Sep 24 2023
STATUS
approved