Search: id:A057092 Results 1-1 of 1 results found. %I A057092 %S A057092 1,9,90,891,8829,87480,866781,8588349,85096170,843160671,8354311569, %T A057092 82777250160,820184055561,8126651751489,80521522263450,797833566134451, %U A057092 7905195795581109,78327264255440040,776092140459190341 %N A057092 Scaled Chebyshev U-polynomials evaluated at i*3/2. Generalized Fibonacci sequence. %C A057092 a(n) gives the length of the word obtained after n steps with the substitution rule 0->1^9, 1->(1^9)0, starting from 0. The number of 1's and 0's of this word is 9*a(n-1) and 9*a(n-2), resp. %D A057092 A. F. Horadam, Special properties of the sequence W_n(a,b; p,q), Fib. Quart., 5.5 (1967), 424-434. Case n->n+1, a=0,b=1; p=9, q=9. %D A057092 W. Lang, On polynomials related to powers of the generating function of Catalan's numbers, Fib. Quart. 38,5 (2000) 408-419; Eqs.(39) and (45),rhs, m=9. %H A057092 Index entries for sequences related to linear recurrences with constant coefficients %H A057092 Tanya Khovanova, Recursive Sequences %H A057092 Index entries for sequences related to Chebyshev polynomials. %F A057092 a(n) = 9*(a(n-1)+a(n-2)), a(-1)=0, a(0)=1. %F A057092 a(n)= S(n, i*3)*(-i*3)^n with S(n, x) := U(n, x/2), Chebyshev's polynomials of the 2nd kind, A049310. %F A057092 G.f.: 1/(1-9*x-9*x^2). %F A057092 a(n)=Sum_{k, 0<=k<=n}8^k*A063967(n,k) . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 03 2006 %F A057092 a(n)=(1/39)*[(9/2)+(3/2)*sqrt(13)]^(n+1)*sqrt(13)-(1/39)*sqrt(13)*[(9/ 2)-(3/2)*sqrt(13)]^(n+1), with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Nov 20 2008] %o A057092 (Other) sage: [lucas_number1(n,9,-9) for n in xrange(1, 20)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 26 2009] %Y A057092 Sequence in context: A054616 A052386 A158609 this_sequence A156577 A052268 A155199 %Y A057092 Adjacent sequences: A057089 A057090 A057091 this_sequence A057093 A057094 A057095 %K A057092 nonn,easy %O A057092 0,2 %A A057092 Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de) Aug 11 2000 Search completed in 0.001 seconds