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A271225
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a(n) = (A268924(n)^2 + 2)/3^n, n >= 0.
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2
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2, 1, 2, 18, 6, 2, 354, 118, 1107, 369, 123, 41, 239803, 495074, 3475362, 1158454, 7887171, 2629057, 56207062, 246253281, 82084427, 5389722857, 25755119139, 8585039713, 53195580742, 193589999521
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OFFSET
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0,1
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COMMENTS
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a(n) is an integer because b(n) = A268924(n) satisfies b(n)^2 + 2 == 0 (mod 3^n), n >= 0.
See A268924 for details, links and references.
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LINKS
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FORMULA
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a(n) = (b(n)^2 + 2)/3^n, n >= 0, with b(n) = A268924(n).
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EXAMPLE
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a(0) = (0^2 + 2)/1 = 2.
a(4) = (22^2 + 2)/3^4 = 6.
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PROG
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(PARI) b(n) = 3^n - truncate(sqrt(-2+O(3^(n))));
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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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