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A104760
Smallest semiprime containing exactly n 7's.
2
57, 77, 3777, 17777, 277777, 1777777, 17777777, 707777777, 3777777777, 17777777777, 577777777777, 1777777777777, 37777777777777, 757777777777777, 4777777777777777, 37777777777777777, 277777777777777777
OFFSET
1,1
EXAMPLE
a(2)=77 because 77 is the smallest semiprime containing exactly two 7's.
CROSSREFS
Sequence in context: A039429 A043252 A044032 * A106662 A087922 A087921
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, Apr 24 2005
STATUS
approved