cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A133773 Number of runs (of equal bits) in the maximal "phinary" (A130601) representation of n.

Original entry on oeis.org

1, 1, 3, 5, 3, 3, 7, 5, 5, 5, 9, 5, 5, 7, 5, 5, 5, 11, 9, 9, 7, 5, 7, 7, 9, 7, 7, 7, 13, 7, 7, 9, 7, 7, 7, 11, 9, 9, 7, 5, 7, 7, 9, 7, 7, 7, 15, 13, 13, 11, 9, 11, 11, 11, 9, 9, 7, 5, 9, 9, 11, 9, 9, 9, 13, 11, 11, 9, 7, 9, 9, 11, 9, 9, 9, 17, 9, 9, 11, 9, 9, 9, 13, 11, 11, 9, 7, 9, 9, 11, 9, 9, 9, 15, 13
Offset: 1

Views

Author

Casey Mongoven, Sep 23 2007

Keywords

Examples

			A130601(3)=1101 because phi^1 + phi^0 + phi^-2 = 3; 1101 has 3 runs: 11,0,1. So a(3)=3.
		

References

  • Zeckendorf, E., Représentation des nombres naturels par une somme des nombres de Fibonacci ou de nombres de Lucas, Bull. Soc. Roy. Sci. Liège 41, 179-182, 1972.

Crossrefs

A133776 Number of 0's in the maximal "phinary" (A130601) representation of n.

Original entry on oeis.org

0, 0, 1, 2, 1, 1, 3, 2, 2, 2, 4, 2, 2, 3, 2, 2, 2, 5, 4, 4, 3, 2, 3, 3, 4, 3, 3, 3, 6, 3, 3, 4, 3, 3, 3, 5, 4, 4, 3, 2, 3, 3, 4, 3, 3, 3, 7, 6, 6, 5, 4, 5, 5, 5, 4, 4, 3, 2, 4, 4, 5, 4, 4, 4, 6, 5, 5, 4, 3, 4, 4, 5, 4, 4, 4, 8, 4, 4, 5, 4, 4, 4, 6, 5, 5, 4, 3, 4, 4, 5, 4, 4, 4, 7, 6, 6, 5, 4, 5, 5, 5, 4, 4, 3, 2
Offset: 1

Views

Author

Casey Mongoven, Sep 23 2007

Keywords

Examples

			A130601(7)=10101101, which has three 0's. So a(7)=3.
		

References

  • Zeckendorf, E., Représentation des nombres naturels par une somme des nombres de Fibonacci ou de nombres de Lucas, Bull. Soc. Roy. Sci. Liège 41, 179-182, 1972.

Crossrefs

A133774 Number of 1s in the maximal "phinary" (A130601) representation of n.

Original entry on oeis.org

1, 3, 3, 3, 6, 6, 5, 6, 6, 6, 5, 9, 9, 8, 9, 9, 9, 7, 8, 8, 9, 10, 9, 9, 8, 9, 9, 9, 7, 12, 12, 11, 12, 12, 12, 10, 11, 11, 12, 13, 12, 12, 11, 12, 12, 12, 9, 10, 10, 11, 12, 11, 11, 11, 12, 12, 13, 14, 12, 12, 11, 12, 12, 12, 10, 11, 11, 12, 13, 12, 12, 11, 12, 12, 12, 9, 15, 15, 14, 15, 15
Offset: 1

Views

Author

Casey Mongoven, Sep 23 2007

Keywords

Examples

			A130601(4)=10101, which contains three 1s. Hence a(4)=3.
		

References

  • E. Zeckendorf, Représentation des nombres naturels par une somme des nombres de Fibonacci ou de nombres de Lucas, Bull. Soc. Roy. Sci. Liège 41, 179-182, 1972.

Crossrefs

A130600 Integers written in base phi, with the "decimal point" omitted.

Original entry on oeis.org

1, 1001, 10001, 10101, 10001001, 10100001, 100000001, 100010001, 100100101, 101000101, 101010101, 100000101001, 100010001001, 100100001001, 100101001001, 101000100001, 101010000001, 1000000000001, 1000001000001
Offset: 1

Views

Author

Casey Mongoven, Aug 06 2007

Keywords

Comments

This is the "greedy" or "minimal" representation (see also A130601).

Examples

			If the decimal point were included, the sequence would read 1., 10.01, 100.01, 101.01, 1000.1001, 1010.0001, 10000.0001, 10001.0001, 10010.0101, 10100.0101, 10101.0101, ... Unfortunately these are not integers.
Examples: a(2)=1001 because phi^1+phi^-2 = 2, a(3) = 10001 because phi^2+phi^-2 = 3, a(4) = 10101 because phi^2+phi^0+phi^-2 = 4.
		

Crossrefs

Programs

  • Mathematica
    nn = 100; len = 2*Ceiling[Log[GoldenRatio, nn]]; Table[d = RealDigits[n, GoldenRatio, len]; last1 = Position[d[[1]], 1][[-1, 1]]; FromDigits[Take[d[[1]], last1]], {n, nn}] (* T. D. Noe, May 20 2011 *)

A289749 Number of ways not ending in 011 to write n in base phi.

Original entry on oeis.org

1, 1, 2, 3, 3, 5, 5, 5, 8, 8, 8, 5, 10, 13, 12, 12, 13, 10, 7, 15, 18, 21, 16, 20, 20, 16, 21, 18, 15, 7, 17, 25, 27, 27, 34, 29, 20, 32, 32, 32, 20, 29, 34, 27, 27, 25, 17, 9, 24, 32, 40, 33, 45, 45, 39, 55, 50, 45, 24, 40, 52, 48, 48, 52, 40, 24, 45, 50, 55, 39, 45, 45
Offset: 0

Views

Author

Gilian Breysens, Jul 11 2017

Keywords

Comments

Old name was: Number of ways to write n in base phi.
phi = (1+sqrt(5))/2. Base phi is also called golden ratio base or phinary. In base phi, we can replace two consecutive 1's with a one in the column to the left; e.g., "011" = "100".
Conjecture: a(A005248(k)) = 2k+1 for k=1,2,...(cf. Theorem 2 in the paper by Carlitz.) - Michel Dekking, Nov 14 2021
This conjecture is proved in the paper "Counting base phi representations". - Michel Dekking, Jul 15 2023

Examples

			a(3) = 3, because 3 in base phi = 10.1111 = 11.01 = 100.01.
		

Crossrefs

Extensions

Name corrected by Michel Dekking, Sep 09 2021
Showing 1-5 of 5 results.