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Search: id:A105046
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| A105046 |
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a(0)=0, a(1)=1, a(2)=8, a(3)=145, a(4)=1298*a(1)-648-a(3), a(5)=1298*a(2)-648-a(2), a(6)=1298*a(3)-a(0)-648-a(1), for n>6 a(n) = 1298*a(n-3) - a(n-6) - 648. |
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+0
1
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| 0, 1, 8, 145, 505, 9728, 187561, 654841, 12626288, 243453385, 849982465, 16388911448, 316002305521
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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It appears this sequence gives all nonnegative m such that 13*m^2 - 13*m + 1 is a square and that a(n+1) = A104240(n) + 1. (A104240 is nonnegative n such that 13*n^2 + 13*n + 1 is a square.)
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FORMULA
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G.f.: x (1+7x+137x^2-938x^3+137x^4+7x^5+x^6) / ((1-x) (1-11x+x^2) (1+11x+120x^2+11x^3+x^4). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 09 2008]
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CROSSREFS
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Cf. A104240.
Adjacent sequences: A105043 A105044 A105045 this_sequence A105047 A105048 A105049
Sequence in context: A024285 A111687 A071305 this_sequence A123812 A064331 A116876
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KEYWORD
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nonn,new
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AUTHOR
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Gerald McGarvey (Gerald.McGarvey(AT)comcast.net), Apr 03 2005
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