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A137280
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a(n) = 3*a(n-1) + 7*a(n-2).
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0
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1, 10, 37, 181, 802, 3673, 16633, 75610, 343261, 1559053, 7079986, 32153329, 146019889, 663132970, 3011538133, 13676545189, 62110402498, 282067023817, 1280973888937, 5817390833530, 26418989723149, 119978705004157
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OFFSET
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1,2
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COMMENTS
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a(n) == 1 mod 9.
a(n)/a(n-1) tends to 4.54138126... = (3 + sqrt(37))/2
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LINKS
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FORMULA
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a(1) = 1, a(2) = 10, a(n), n>2 = 3*a(n-1) + 7*a(n-2). a(n) = upper left term in [1,3; 3,2]^n
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EXAMPLE
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a(4) = 181 = 3*a(3) + 7*a(2) = 3*37 + 7*10.
a(4) = 181 = upper left term in [1,3; 3,2]^4.
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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