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A157838
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3600n^2 - 6049n + 2541.
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3
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92, 4843, 16794, 35945, 62296, 95847, 136598, 184549, 239700, 302051, 371602, 448353, 532304, 623455, 721806, 827357, 940108, 1060059, 1187210, 1321561, 1463112, 1611863, 1767814, 1930965, 2101316, 2278867, 2463618, 2655569
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OFFSET
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1,1
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COMMENTS
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The identity (103680000*n^2-174211200*n+73180801)^2-(3600*n^2-6049*n+2541)*(1728000*n-1451760)^2=1 can be written as A157840(n)^2-a(n)*A157839(n)^2=1.
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LINKS
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FORMULA
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a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: x*(-92-4567*x-2541*x^2)/(x-1)^3.
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {92, 4843, 16794}, 40]
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PROG
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(Magma) I:=[92, 4843, 16794]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]];
(PARI) a(n) = 3600*n^2 - 6049*n + 2541.
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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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