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A064160
Numbers k such that the digits of k joined to the digits of 2k contain each of the digits from 1 to 9 once.
5
6729, 6792, 6927, 7269, 7293, 7329, 7692, 7923, 7932, 9267, 9273, 9327
OFFSET
0,1
REFERENCES
David Wells, The Penguin Dictionary of Curious and Interesting Numbers, p. 160 (Rev. ed. 1997).
EXAMPLE
Twice 7269 equals 14538 and those two numbers comprise the digits from 1 to 9.
MATHEMATICA
Select[ Range[ 1000000 ], {1, 2, 3, 4, 5, 6, 7, 8, 9} == Sort[ Join[ IntegerDigits[ # ], IntegerDigits[ 2 # ] ] ] & ]
CROSSREFS
Sequence in context: A035905 A099778 A049507 * A249463 A031642 A257486
KEYWORD
base,fini,full,nonn
AUTHOR
Harvey P. Dale, Sep 15 2001
STATUS
approved