The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A136010 a(0)=20, a(1)=9; for n >= 0, a(n+2) = 7*a(n+1) + 9*a(n). 1
 20, 9, 243, 1782, 14661, 118665, 962604, 7806213, 63306927, 513404406, 4163593185, 33765791949, 273832882308, 2220722303697, 18009552066651, 146053365199830, 1184459524998669, 9605696961789153, 77900014457512092 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS From an online IQ test (Adaptive IQ). LINKS G. C. Greubel, Table of n, a(n) for n = 0..999 [Offset shifted by Georg Fischer, Jun 18 2021] Index entries for linear recurrences with constant coefficients, signature (7,9). FORMULA G.f.: (20 - 131*x)/(1-7*x-9*x^2). - M. F. Hasler, Mar 27 2008 a(n) = (10 + 61/sqrt(85))*(7/2 - sqrt(85)/2)^n + (10 - 61/sqrt(85))*(7/2 + sqrt(85)/2)^n. - Alexander R. Povolotsky, simplified by M. F. Hasler, Mar 29 2008 MAPLE A136010:=n -> simplify((10+61/sqrt(85))*(7/2-1/2*sqrt(85))^n+(10-61/sqrt(85))*(7/2+1/2*sqrt(85))^n); # M. F. Hasler, Mar 29 2008 MATHEMATICA LinearRecurrence[{7, 9}, {20, 9}, 50] (* G. C. Greubel, Feb 21 2017 *) PROG (PARI) A136010(n) = { local(y=Mod(x, x^2-85)); lift((10+61/y)*(7/2-1/2*y)^n+(10-61/y)*(7/2+1/2*y)^n)} \\ M. F. Hasler, improved by Max Alekseyev, Mar 29 2008 (PARI) my(x='x+O('x^50)); Vec((20 - 131*x)/(1-7*x-9*x^2)) \\ G. C. Greubel, Feb 21 2017 CROSSREFS Sequence in context: A040384 A078080 A216289 * A091534 A033966 A033340 Adjacent sequences: A136007 A136008 A136009 * A136011 A136012 A136013 KEYWORD nonn,easy AUTHOR Jordan Giedd (jordyg365(AT)gmail.com), Mar 20 2008 EXTENSIONS Definition supplied by Don Reble, Mar 27 2008 Offset corrected by Georg Fischer, Jun 18 2021 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 25 19:44 EST 2024. Contains 370332 sequences. (Running on oeis4.)