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a(n) = 25*n + 1.
1

%I #23 Sep 08 2022 08:45:42

%S 26,51,76,101,126,151,176,201,226,251,276,301,326,351,376,401,426,451,

%T 476,501,526,551,576,601,626,651,676,701,726,751,776,801,826,851,876,

%U 901,926,951,976,1001,1026,1051,1076,1101,1126,1151,1176,1201,1226,1251

%N a(n) = 25*n + 1.

%H Vincenzo Librandi, <a href="/A158060/b158060.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

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

%F G.f.: x*(26-x)/(x-1)^2.

%t LinearRecurrence[{2,-1},{26,51},50]

%t Range[26, 2000, 25] (* _Vladimir Joseph Stephan Orlovsky_, Jun 14 2011 *)

%t 25*Range[50]+1 (* _Harvey P. Dale_, Nov 23 2018 *)

%o (Magma) I:=[26, 51]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..60]];

%o (PARI) a(n)=25*n+1 \\ _Charles R Greathouse IV_, Jun 14 2011

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Mar 12 2009