%I A015532
%S A015532 0,1,4,23,120,641,3404,18103,96240,511681,2720404,14463383,76896360,
%T A015532 408829121,2173591004,11556167863,61439808480,326652408961,
%U A015532 1736688295204,9233320043543,49090098240600,260993633267201
%N A015532 a(n) = 4 a(n-1) + 7 a(n-2).
%F A015532 O.g.f.: -x/(-1+4*x+7*x^2). a(n)=-7^n*(A^n-B^n)/(2sqrt(11)) where A=-1/
               (2+sqrt(11)) and B=1/(sqrt(11)-2) . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Apr 29 2008
%o A015532 (Other) sage: [lucas_number1(n,4,-7) for n in xrange(0, 21)]# [From Zerinvary 
               Lajos (zerinvarylajos(AT)yahoo.com), Apr 23 2009]
%Y A015532 Sequence in context: A082970 A017973 A124507 this_sequence A144465 A024050 
               A038723
%Y A015532 Adjacent sequences: A015529 A015530 A015531 this_sequence A015533 A015534 
               A015535
%K A015532 nonn,easy
%O A015532 0,3
%A A015532 Olivier Gerard (olivier.gerard(AT)gmail.com)