This site is supported by donations to The OEIS Foundation.

The October issue of the Notices of the Amer. Math. Soc. has an article about the OEIS.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A055271 a(n) = 5a(n-1) - a(n-2); a(0)=1, a(1)=7. 3
 1, 7, 34, 163, 781, 3742, 17929, 85903, 411586, 1972027, 9448549, 45270718, 216905041, 1039254487, 4979367394, 23857582483, 114308545021, 547685142622, 2624117168089, 12572900697823, 60240386321026, 288629030907307 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 122-125, 194-196. LINKS I. Adler, Three Diophantine equations - Part II, Fib. Quart., 7 (1969), pp. 181-193. E. I. Emerson, Recurrent Sequences in the Equation DQ^2=R^2+N, Fib. Quart., 7 (1969), pp. 231-242. Tanya Khovanova, Recursive Sequences Index entries for linear recurrences with constant coefficients, signature (5,-1). FORMULA a(n) = (7*(((5+sqrt(21))/2)^n - ((5-sqrt(21))/2)^n) - (((5+sqrt(21))/2)^(n-1) - ((5-sqrt(21))/2)^(n-1)))/sqrt(21). G.f.: (1+2*x)/(1-5*x+x^2). a(n) = (-1)^n*Sum_{k = 0..n} A238731(n,k)*(-8)^k. - Philippe Deléham, Mar 05 2014 CROSSREFS Cf. A030221. Sequence in context: A099242 A032206 A124466 * A209890 A027209 A209807 Adjacent sequences:  A055268 A055269 A055270 * A055272 A055273 A055274 KEYWORD easy,nonn AUTHOR Barry E. Williams, May 10 2000 STATUS approved

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

Last modified September 22 18:50 EDT 2018. Contains 315270 sequences. (Running on oeis4.)