OFFSET
0,3
COMMENTS
A Fibonacci tree of order n (n>=2) is a complete binary tree whose left subtree is the Fibonacci tree of order n-1 and whose right subtree is the Fibonacci tree of order n-2; each of the Fibonacci trees of order 0 and 1 is defined as a single node. In a Fibonacci tree the cost of a left (right) edge is defined to be 1 (2). The cost of a node in a Fibonacci tree is defined to be the sum of the costs of the edges that form the path from the root to this node.
A178525 is the 1-sequence of reduction of the odd number sequence (2n-1) by x^2 -> x+1; as such it is related to 0-sequence of this reduction, A192304. See A192232 for definition of "k-sequence of reduction of [sequence] by [substitution]". - Clark Kimberling, Jun 27 2011
REFERENCES
D. E. Knuth, The Art of Computer Programming, Vol. 3, 2nd edition, Addison-Wesley, Reading, MA, 1998, p. 417.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Y. Horibe, An entropy view of Fibonacci trees, Fibonacci Quarterly, 20, No. 2, 1982, 168-178.
Index entries for linear recurrences with constant coefficients, signature (3,-1,-3,1,1).
FORMULA
a(n) = 3 + (2*n-3)*F(n-1) + (2*n-5)*F(n), where F(k)=A000045(k) are the Fibonacci numbers.
a(n) = a(n-1) + a(n-2) + 2*F(n+1) + 2*F(n-1) - 3 (n>=2), F(0)=0, F(1)=0.
G.f.: z^2*(3-z+z^2)/((1-z)*(1-z-z^2)^2).
MAPLE
with(combinat): seq(3+(2*n-3)*fibonacci(n-1)+(2*n-5)*fibonacci(n), n = 0 .. 32);
MATHEMATICA
Table[3 +(2*n-3)*Fibonacci[n-1] +(2*n-5)*Fibonacci[n], {n, 0, 40}] (* G. C. Greubel, Jan 30 2019 *)
PROG
(PARI) a(n) = 3+(2*n-3)*fibonacci(n-1) + (2*n-5)*fibonacci(n); \\ Michel Marcus, Jan 21 2019
(Magma) [3 +(2*n-3)*Fibonacci(n-1) +(2*n-5)*Fibonacci(n): n in [0..40]]; // G. C. Greubel, Jan 30 2019
(Sage) [3 +(2*n-3)*fibonacci(n-1) +(2*n-5)*fibonacci(n) for n in range(40)] # G. C. Greubel, Jan 30 2019
(GAP) List([0..40], n -> 3 +(2*n-3)*Fibonacci(n-1) +(2*n-5)*Fibonacci(n)); # G. C. Greubel, Jan 30 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Jun 15 2010
STATUS
approved