OFFSET
1,3
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
81 is not a term since in 81^2 = 6561, the two 6's are separated by the 5.
88 is a term since in 88^2 = 7744, the 7 and 4 are grouped.
MAPLE
filter:= proc(n) local L, i, v, V;
L:= convert(n^2, base, 10);
for i from 1 to nops(L) do
v:= L[i];
if not assigned(V[v]) then V[v]:= i
elif V[v] < i-1 then return false
else V[v]:= i
fi
od;
true
end proc:
select(filter, [$0..100]); # Robert Israel, Nov 08 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Jan 15 2000
STATUS
approved