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A156853
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2025n^2 - 649n + 52.
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4
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1428, 6854, 16330, 29856, 47432, 69058, 94734, 124460, 158236, 196062, 237938, 283864, 333840, 387866, 445942, 508068, 574244, 644470, 718746, 797072, 879448, 965874, 1056350, 1150876, 1249452, 1352078, 1458754, 1569480, 1684256
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity(32805000*n^2-55096200*n+23133601)^2-(2025*n^2-649*n+52)*(729000*n-612180)^2=1 can be written as A157078(n)^2-a(n)*A156865(n)^2=1.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
| a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f.: x*(-1428-2570*x-52*x^2)/(x-1)^3.
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MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {1428, 6854, 16330}, 40]
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PROG
| (MAGMA) I:=[1428, 6854, 16330]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..30]];
(PARI) a(n)=2025*n^2-649*n+52 \\ Charles R Greathouse IV, Dec 23 2011
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CROSSREFS
| Cf. A156865, A157078.
Sequence in context: A153426 A068572 A163589 * A094230 A060364 A124087
Adjacent sequences: A156850 A156851 A156852 * A156854 A156855 A156856
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Feb 17 2009
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