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A010007
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a(0) = 1, a(n) = 17*n^2 + 2 for n>0.
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1
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1, 19, 70, 155, 274, 427, 614, 835, 1090, 1379, 1702, 2059, 2450, 2875, 3334, 3827, 4354, 4915, 5510, 6139, 6802, 7499, 8230, 8995, 9794, 10627, 11494, 12395, 13330, 14299, 15302, 16339, 17410, 18515, 19654, 20827, 22034, 23275, 24550, 25859, 27202, 28579
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OFFSET
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0,2
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COMMENTS
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Apart from the first term, numbers of the form (r^2+2*s^2)*n^2+2 = (r*n)^2+(s*n-1)^2+(s*n+1)^2: in this case is r=3, s=2. After 1, all terms are in A000408. - Bruno Berselli, Feb 06 2012
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LINKS
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FORMULA
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MATHEMATICA
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Join[{1}, LinearRecurrence[{3, -3, 1}, {19, 70, 155}, 50]] (* Vincenzo Librandi, Aug 03 2015 *)
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PROG
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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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EXTENSIONS
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STATUS
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approved
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