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A157947 98n + 1. 2
99, 197, 295, 393, 491, 589, 687, 785, 883, 981, 1079, 1177, 1275, 1373, 1471, 1569, 1667, 1765, 1863, 1961, 2059, 2157, 2255, 2353, 2451, 2549, 2647, 2745, 2843, 2941, 3039, 3137, 3235, 3333, 3431, 3529, 3627, 3725, 3823, 3921, 4019, 4117, 4215, 4313 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The identity (98*n+1)^2-(49*n^2+n)*14^2 = 1 can be written as a(n)^2-A173141(n)*14^2 = 1. - Vincenzo Librandi, Feb 10 2012

LINKS

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

E. J. Barbeau, Polynomial Excursions, Chapter 10: Diophantine equations (2010), pages 84-85 (row 14 in the first table at p. 85, case d(t) = t*(7^2*t+1)).

Index to sequences with linear recurrences with constant coefficients, signature (2,-1).

FORMULA

a(n) = 2*a(n-1)-a(n-2). - Vincenzo Librandi, Feb 10 2012

G.f.: x*(99-x)/(1-x)^2. - Vincenzo Librandi, Feb 10 2012

MATHEMATICA

LinearRecurrence[{2, -1}, {99, 197}, 50] (* Vincenzo Librandi, Feb 10 2012 *)

PROG

(MAGMA) I:=[99, 197]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Feb 10 2012

(PARI) for(n=1, 50, print1(98n + 1", ")); \\ Vincenzo Librandi, Feb 10 2012

CROSSREFS

Cf. A173141.

Sequence in context: A055164 A075815 A075814 * A097599 A033674 A043526

Adjacent sequences:  A157944 A157945 A157946 * A157948 A157949 A157950

KEYWORD

nonn,easy,changed

AUTHOR

Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 10 2009

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Last modified February 15 02:50 EST 2012. Contains 205694 sequences.