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A157855 103680000n^2 - 46108800n + 5126401. 3
62697601, 327628801, 799920001, 1479571201, 2366582401, 3460953601, 4762684801, 6271776001, 7988227201, 9912038401, 12043209601, 14381740801, 16927632001, 19680883201, 22641494401, 25809465601, 29184796801, 32767488001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The identity (103680000*n^2-46108800*n+5126401)^2-(3600*n^2-1601*n +178)*(1728000*n-384240)^2=1 can be written as a(n)^2-A157853(n)*A157854(n)^2=1.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..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.: x*(-62697601-139535998*x-5126401*x^2)/(x-1)^3.

MATHEMATICA

LinearRecurrence[{3, -3, 1}, {62697601, 327628801, 799920001}, 40]

PROG

(MAGMA) I:=[62697601, 327628801, 799920001]; [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) = 103680000*n^2 - 46108800*n + 5126401.

CROSSREFS

Cf. A157853, A157854.

Sequence in context: A205658 A206187 A205369 * A017539 A227150 A186140

Adjacent sequences:  A157852 A157853 A157854 * A157856 A157857 A157858

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Mar 08 2009

STATUS

approved

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Last modified October 23 21:27 EDT 2021. Contains 348217 sequences. (Running on oeis4.)