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
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