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A137059
Numbers k such that k and k^2 use only the digits 1, 4, 8 and 9.
0
1, 9, 141, 441, 1191
OFFSET
1,2
COMMENTS
Generated with DrScheme.
No more terms up to 10^27. - Robert Israel, Nov 23 2023
LINKS
EXAMPLE
1191^2 = 1418481.
MAPLE
Good:= {1, 4, 8, 9}:
R:= 1, 9:
G[1]:= select(t -> member(t^2 mod 10, Good), Good):
for d from 2 to 27 do
G[d]:= select(t -> member(floor((t^2 mod 10^d)/10^(d-1)), Good), map(t -> seq(10^(d-1)*i+t, i=Good), G[d-1]));
for t in G[d] do
if convert(convert(t^2, base, 10), set) subset Good then R:= R, t fi
od
od:
R; # Robert Israel, Nov 23 2023
CROSSREFS
Sequence in context: A266634 A092652 A137051 * A263966 A371365 A083084
KEYWORD
base,nonn,more
AUTHOR
Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
STATUS
approved