A137059 Numbers k such that k and k^2 use only the digits 1, 4, 8 and 9.

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

Table of n, a(n) for n=1..5.

Jonathan Wellons, Tables of Shared Digits [archived]

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

Adjacent sequences: A137056 A137057 A137058 * A137060 A137061 A137062

Keyword

base,nonn,more

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Status

approved