OFFSET
1,1
COMMENTS
REFERENCES
George E. Martin, Geometric Constructions, New York: Springer, 1997, p. 140.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,0,2).
FORMULA
G.f.: x*(3*x^7 + 2*x^6 + 2*x^5 + 2*x^4 + 6*x^3 + 5*x^2 + 4*x + 3)/(1 - 2*x^4).
a(n+4) = 2*a(n) for n > 8. - Reinhard Zumkeller, Mar 19 2010
Sum_{n>=1} 1/a(n) = 17/10. - Amiram Eldar, Jan 18 2023
MATHEMATICA
CoefficientList[Series[x(3x^7+2x^6+2x^5+2x^4+6x^3+5x^2+4x+3)/(1-2x^4), {x, 0, 60}], x] (* Harvey P. Dale, Dec 23 2012 *)
PROG
(PARI) Vec(x*(3*x^7+2*x^6+2*x^5+2*x^4+6*x^3+5*x^2+4*x+3)/(1-2*x^4)+O(x^99)) \\ Charles R Greathouse IV, Oct 12 2012
CROSSREFS
KEYWORD
nonn,easy,nice
AUTHOR
Antreas P. Hatzipolakis (xpolakis(AT)otenet.gr), Dec 17 1999
EXTENSIONS
More terms from James A. Sellers, Dec 18 1999
Offset corrected by Reinhard Zumkeller, Mar 10 2010
STATUS
approved