A156845 - OEIS

A156845

a(n) = 12167*n - 8579.

3588, 15755, 27922, 40089, 52256, 64423, 76590, 88757, 100924, 113091, 125258, 137425, 149592, 161759, 173926, 186093, 198260, 210427, 222594, 234761, 246928, 259095, 271262, 283429, 295596, 307763, 319930, 332097, 344264, 356431, 368598

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OFFSET

1,1

COMMENTS

The identity (279841*n^2-394634*n+139128)^2-(529*n^2-746*n+263)*(12167*n-8579)^2=1 can be written as A156844(n)^2-A156842(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*(3588+8579*x)/(x-1)^2.

MATHEMATICA

LinearRecurrence[{2, -1}, {3588, 15755}, 40]

PROG

(Magma) I:=[3588, 15755]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];

(PARI) a(n)=12167*n-8579 \\ Charles R Greathouse IV, Dec 23 2011

CROSSREFS

CF. A156842, A156844, A156849.

Sequence in context: A234138 A249289 A249537 * A174851 A342970 A284970

Adjacent sequences: A156842 A156843 A156844 * A156846 A156847 A156848

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Feb 17 2009

STATUS

approved