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%I #14 Apr 24 2021 10:26:10
%S 4,24,47,471,487,1248,1249,6248,6249,6249,12493,12493,12493,12493,
%T 12498,31249,62499,62499,62499,62499,62499,62499,62499,62499,62499,
%U 62499,62499,62499,62499,62499,62499,312497,312497,312497,624984,624984,624984,624984,624984
%N Smallest k for which k, 2k, ... nk all contain the digit 4.
%H Giovanni Resta, <a href="/A039935/b039935.txt">Table of n, a(n) for n = 1..2047</a>
%e a(3) = 47 since 47, 94 and 141 all contain a 4.
%o (Python)
%o def aupton(terms):
%o k, n, alst = 1, 1, []
%o while len(alst) < terms:
%o while not all(str(i*k).count('4') > 0 for i in range(1, n+1)): k += 1
%o while str(n*k).count('4') > 0: alst.append(k); n += 1
%o k += 1
%o return alst[:terms]
%o print(aupton(39)) # _Michael S. Branicky_, Apr 24 2021
%Y Cf. A039932, A039933, A039934, A039936, A039937, A039938, A039939, A039940.
%K base,nonn
%O 1,1
%A _Erich Friedman_
%E More terms from _Patrick De Geest_, Oct 15 1999
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