OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
EXAMPLE
45 = 231_4 and 45^2 = 133221_4.
MAPLE
p:= n-> add(x^i, i=convert(n, base, 4)):
a:= proc(n) option remember; local k;
for k from 1+`if`(n=1, 0, a(n-1))
while p(k)*2<>p(k^2) do od; k
end:
seq(a(n), n=1..50); # Alois P. Heinz, May 10 2015
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Erich Friedman, Jun 16 2001
EXTENSIONS
Offset changed to 1 by Alois P. Heinz, May 10 2015
STATUS
approved