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%I #18 Feb 17 2021 11:38:36
%S 2,17,144,1447,14144,141494,1414414,14144134,141431114,1414411113,
%T 14143143413,141431113114,1414311131114,14143111141813,
%U 141431113114113,1414311344113314,14143111141141113,141431113114331413
%N Least n-digit number m whose square contains only digits not appearing in m.
%C floor(sqrt(2)*10^(n-1)) < a(n). - _Robert G. Wilson v_, Oct 04 2005
%t f[n_] := Block[{k = Ceiling[10^n*(1/9 + .03032)]}, While[ Intersection[ IntegerDigits[k], IntegerDigits[k^2]] != {}, k++ ]; k]; Table[ f[n], {n, 18}] (* _Robert G. Wilson v_ *)
%o (Python)
%o from math import isqrt
%o def a(n):
%o m = isqrt(int('2'+'0'*(2*n-2)))
%o while set(str(m*m)) & set(str(m)) != set(): m += 1
%o return m
%o print([a(n) for n in range(1, 12)]) # _Michael S. Branicky_, Feb 17 2021
%Y Cf. A110816 (corresponding squares), A112321. Subsequence of A029783.
%K nonn,base
%O 1,1
%A _Lekraj Beedassy_, Aug 17 2005
%E a(3) to a(6) corrected, a(7) to a(13) from _Klaus Brockhaus_, Aug 31 2005; revised Sep 09 2005
%E a(14)-a(18) from _Robert G. Wilson v_, Oct 04 2005
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