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
KEYWORD
base,fini,full,nonn
AUTHOR
Harvey P. Dale, Sep 15 2001
STATUS
approved