login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

a(1)=5, a(2)=2, a(n) = 5*a(n-1) + 2*a(n-2)
12

%I #30 Feb 18 2024 03:34:39

%S 5,2,20,104,560,3008,16160,86816,466400,2505632,13460960,72316064,

%T 388502240,2087143328,11212721120,60237892256,323614903520,

%U 1738550302112,9339981317600,50177007192224,269564998596320,1448179007366048,7780025034022880,41796483184846496

%N a(1)=5, a(2)=2, a(n) = 5*a(n-1) + 2*a(n-2)

%H Vincenzo Librandi, <a href="/A189746/b189746.txt">Table of n, a(n) for n = 1..100</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (5,2).

%F G.f.: x*(5-23*x)/(1-5*x-2*x^2). - _Bruno Berselli_, May 24 2011

%t LinearRecurrence[{5,2},{5,2},40]

%o (Maxima) a[1]:5$ a[2]:2$ a[n]:=5*a[n-1]+2*a[n-2]$ makelist(a[n], n, 1, 24); /* _Bruno Berselli_, May 24 2011 */

%Y Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189736, A189737, A189738, A189739, A189741, A189742, A189743, A189744, A189745, A189747, A189748, A189749.

%K nonn,easy

%O 1,1

%A _Harvey P. Dale_, Apr 26 2011