A156843 - OEIS

A156843

279841n^2 - 165048n + 24335.

24335, 139128, 813603, 2047760, 3841599, 6195120, 9108323, 12581208, 16613775, 21206024, 26357955, 32069568, 38340863, 45171840, 52562499, 60512840, 69022863, 78092568, 87721955, 97911024, 108659775, 119968208, 131836323

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OFFSET

0,1

COMMENTS

The identity (279841*n^2-165048*n+24335)^2-(529*n^2-312*n+46)*(12167*n-3588)^2=1 can be written as a(n)^2-A156841(n)*A156846(n)^2=1 for n>0.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).

G.f.: (24335+66123*x+469224*x^2)/(1-x)^3.

MATHEMATICA

LinearRecurrence[{3, -3, 1}, {24335, 139128, 813603}, 40]

PROG

(Magma) I:=[24335, 139128, 813603]; [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)= 279841*n^2-165048*n+24335 \\ Charles R Greathouse IV, Dec 23 2011

CROSSREFS

Cf. A156841, A156846, A156849.

Sequence in context: A208622 A294856 A025041 * A156844 A174754 A206682

Adjacent sequences: A156840 A156841 A156842 * A156844 A156845 A156846

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Feb 17 2009

EXTENSIONS

Edited by Charles R Greathouse IV, Jul 25 2010

STATUS

approved