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A204846
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Irregular triangle read by rows in which row n lists algebraic prime factors of the repunit (10^n - 1)/9 (A002275(n)).
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5
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1, 1, 1, 11, 1, 3, 11, 37, 1, 11, 101, 3, 37, 11, 41, 271
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,4
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REFERENCES
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Samuel Yates, The Mystique of Repunits, Math. Mag. 51 (1978), 22-28.
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LINKS
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Table of n, a(n) for n=1..16.
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EXAMPLE
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Triangle begins: 1
1
1
11
1
3,11,37
1
11,101
3,37
11,41,271
...
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CROSSREFS
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Cf. A002275, A102380, A204845.
Sequence in context: A039617 A214676 A010198 * A127991 A110305 A010199
Adjacent sequences: A204843 A204844 A204845 * A204847 A204848 A204849
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KEYWORD
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nonn,tabf,more
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AUTHOR
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N. J. A. Sloane, Jan 19 2012
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STATUS
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approved
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