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A157105 137842n - 30996. 4
106846, 244688, 382530, 520372, 658214, 796056, 933898, 1071740, 1209582, 1347424, 1485266, 1623108, 1760950, 1898792, 2036634, 2174476, 2312318, 2450160, 2588002, 2725844, 2863686, 3001528, 3139370, 3277212, 3415054 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The identity (5651522*n^2-2541672*n+285769)^2-(1681*n^2-756*n+85)*(137842*n-30996)^2=1 can be written as (A157106(n))^2-(A157010(n))*(a(n))^2=1.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

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

G.f: x*(106846+30996*x)/(x-1)^2.

MATHEMATICA

LinearRecurrence[{2, -1}, {106846, 244688}, 30] (* Harvey P. Dale, Mar 31 2013 *)

PROG

(MAGMA) I:=[106846, 244688, 382530]; [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) = 137842*n - 30996

CROSSREFS

Cf. A157010, A157106.

Sequence in context: A253404 A223343 A028466 * A122711 A297994 A237216

Adjacent sequences:  A157102 A157103 A157104 * A157106 A157107 A157108

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Feb 23 2009

STATUS

approved

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Last modified May 18 00:43 EDT 2021. Contains 343992 sequences. (Running on oeis4.)