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A039935
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Smallest k for which k, 2k, ... nk all contain the digit 4.
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9
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4, 24, 47, 471, 487, 1248, 1249, 6248, 6249, 6249, 12493, 12493, 12493, 12493, 12498, 31249, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 62499, 312497, 312497, 312497, 624984, 624984, 624984, 624984, 624984
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(3) = 47 since 47, 94 and 141 all contain a 4.
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PROG
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(Python)
def aupton(terms):
k, n, alst = 1, 1, []
while len(alst) < terms:
while not all(str(i*k).count('4') > 0 for i in range(1, n+1)): k += 1
while str(n*k).count('4') > 0: alst.append(k); n += 1
k += 1
return alst[:terms]
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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