A157797 - OEIS

A157797

a(n) = 8984250*n - 1996170.

6988080, 15972330, 24956580, 33940830, 42925080, 51909330, 60893580, 69877830, 78862080, 87846330, 96830580, 105814830, 114799080, 123783330, 132767580, 141751830, 150736080, 159720330, 168704580, 177688830, 186673080, 195657330

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OFFSET

1,1

COMMENTS

The identity (1482401250*n^2-658736100*n+73180801)^2-(27225*n^2-12098*n+1344)*(8984250*n-1996170)^2=1 can be written as A157798(n)^2-A157796(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*(6988080 + 1996170*x)/(1 - x)^2.

MATHEMATICA

LinearRecurrence[{2, -1}, {6988080, 15972330}, 30]

PROG

(Magma) I:=[6988080, 15972330]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..30]];

(PARI) a(n) = 8984250*n - 1996170;

CROSSREFS