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Search: id:A053655
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| A053655 |
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a(n)=(10^n-1)*(10^(2*n-1)-1)/81. |
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+0
1
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| 1, 1221, 1233321, 1234444321, 1234555554321, 1234566666654321, 1234567777777654321, 1234567888888887654321, 1234567899999999987654321, 1234567901111111110987654321, 1234567901222222222220987654321
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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W. Lietzmann, Sonderlinge im Reich der Zahlen, Ferd. Duemmlers Verlag Bonn, 1948, p. 30.
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EXAMPLE
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a(2)=11*111=1221; a(3)=111*11111=1233321; a(49=1111*1111111=1234444321.
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CROSSREFS
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Sequence in context: A069400 A015279 A091790 this_sequence A068262 A128655 A014488
Adjacent sequences: A053652 A053653 A053654 this_sequence A053656 A053657 A053658
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KEYWORD
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easy,nonn
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AUTHOR
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Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Feb 17 2000
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