A126723 Successive rows of coefficients c(0), c(1), c(2),... for the greedy-algorithm representation of a positive integer n: n = c(0)/x + c(1)/x^2 + c(2)/x^3 + ..., where x = (1+sqrt(5))/2.

1, 1, 3, 0, 0, 1, 4, 1, 0, 1, 6, 0, 1, 0, 0, 1, 8, 0, 0, 0, 0, 1, 9, 1, 0, 0, 0, 1, 11, 0, 0, 1, 0, 1, 12, 1, 0, 1, 0, 1, 14, 0, 1, 0, 1, 0, 0, 1, 16, 0, 0, 0, 1, 0, 0, 1, 17, 1, 0, 0, 1, 0, 0, 1, 19, 0, 1, 0, 0, 0, 0, 1, 21, 0, 0, 0, 0, 0, 0, 1, 22, 1, 0, 0, 0, 0, 0, 1, 24, 0, 0, 1, 0, 0, 0, 1, 25, 1, 0, 1

Offset

1,3

Comments

Max Alekseyev (see link below) proved the following: suppose that N = c(1)F(1) - c(2)F(2) + c(3)F(3) - ..., where F(i) are Fibonacci numbers and each coefficient c(i) is either 0 or 1 with no adjacent unit coefficients. Then these coefficients are exactly those produced by the greedy algorithm: N = c(0)/x + c(1)/x^2 + c(2)/x^3 + ... . It follows that there are only finitely many nonzero terms and that the representation is unique for the stated properties.

c(0)=Floor(N*x) (as in A000201, the lower Wythoff sequence). Thus as N*x-c(0) is the fractional part {N*x} of N*x, we have {N*x} represented as a sum of finitely many fractions 1/x^k.

Links

Table of n, a(n) for n=1..100.

Max Alekseyev, Re: Representations found by the greedy algorithm, SeqFan Mailing List, Dec 19 2006

Example

First five rows:
1 1
3 0 0 1
4 1 0 1
6 0 1 0 0 1
8 0 0 0 0 1
Row 4 matches 6 = 6/x + 0/x^2 + 1/x^3 + 0/x^4 + 0/x^5 + 1/x^6.

Crossrefs

Cf. A000045, A000201.

Sequence in context: A170840 A300725 A035630 * A325846 A325735 A235794

Adjacent sequences: A126720 A126721 A126722 * A126724 A126725 A126726

Keyword

nonn,tabf

Author

Clark Kimberling, Dec 23 2006

Status

approved