OFFSET
1,1
COMMENTS
Graham shows that this sequence is (eventually) complete, that is, any large enough number can be written as a sum of finitely many terms of this sequence, and that it retains this property if any finite number of terms are removed, but loses this property if any infinite number of terms are removed. Contrast with the Fibonacci numbers, which retain the property with loss of any one but lose it with the removal of any two. - Charles R Greathouse IV, Dec 20 2013
REFERENCES
R. Honsberger, Mathematical Gems III, M.A.A., 1985, p. 129.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
R. L. Graham, A property of Fibonacci numbers, Fibonacci Quarterly 2:1 (1964), pp. 1-10.
Index entries for linear recurrences with constant coefficients, signature (0,2,1).
FORMULA
G.f.: x*(2-x^2)/((1+x)*(1-x-x^2)).
a(n) = 2*(n-2)+a(n-3).
MAPLE
with(combinat): A007492 := n->fibonacci(n)-(-1)^n;
MATHEMATICA
Table[Fibonacci[n] - (-1)^n, {n, 40}] (* Bruno Berselli, Dec 20 2013 *)
PROG
(PARI) a(n)=fibonacci(n)-(-1)^n
(Magma) [(Fibonacci(n)-(-1)^n): n in [1..55]]; // Vincenzo Librandi, Apr 23 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Michael Somos, Apr 28, 2000.
STATUS
approved