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Search: id:A101180
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| A101180 |
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Numbers n such that 19*n^2 + 19*n + 1 is a square. |
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+0
2
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| 0, 8, 671, 15639, 42159, 981911, 77624048, 1807894920, 4873553880, 113507005568, 8973184757831, 208989037004319, 563373081435879
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Define a(1)=0, a(2)=8, a(3)=671, a(4)=15639, a(5)=42159, a(6)=981911, the first 6 terms found for the sequence then a(7)=57799*(2*a(3)+1)-a(2)-1, a(8)=57799*(2*a(4)+1)-a(1)-1 for n>8 a(n)=57799*(2*a(n-4)+1)-a(n-8)-1 remark:57799 = 38*39*39+1 =2*19*(39^2)+1
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CROSSREFS
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Cf. A105839.
Sequence in context: A159621 A015106 A099126 this_sequence A128875 A037076 A116245
Adjacent sequences: A101177 A101178 A101179 this_sequence A101181 A101182 A101183
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KEYWORD
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nonn,more
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AUTHOR
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Pierre CAMI (pierrecami(AT)tele2.fr), Apr 06 2005, Apr 22 2005
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Aug 29 2008 at the suggestion of R. J. Mathar
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