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A286720 Number of Egyptian fractions in the representation of 1-1/(2n+1) by the odd greedy expansion algorithm, without repeats. 2
4, 6, 6, 4, 6, 6, 4, 6, 6, 6, 8, 6, 6, 10, 6, 6, 8, 6, 12, 10, 10, 4, 6, 6, 6, 8, 6, 6, 8, 10, 6, 6, 8, 8, 6, 10, 6, 8, 6, 8, 6, 10, 6, 10, 6, 10, 6, 10, 6, 8, 8, 6, 8, 8, 8, 6, 6, 6, 10, 8, 6, 8, 10, 12, 8, 10, 6, 8, 8, 8, 10, 8, 6, 8, 10, 6, 8, 8, 6, 6, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The odd version of A100678.

LINKS

Table of n, a(n) for n=1..81.

Kevin Brown, Odd-Greedy Unit Fraction Expansions

Wikipedia, Odd greedy expansion

EXAMPLE

For n = 1, 1-1/(2n+1) = 2/3 = 1/3 + 1/5 + 1/9 + 1/45 has 4 fractions in the representation, thus a(1) = 4.

MATHEMATICA

odd[n_]:=If[OddQ[n], n, n+1]; a={}; For[n=0, n<100, n++; lst={}; k=2n/(2n+1); s1=0; While[k>0, s2=odd[Ceiling[1/k]]; If[s2==s1, s2+=2]; AppendTo[lst, s2]; k=k-1/s2; s1=s2]; a=AppendTo[a, Length[lst]]]; a

CROSSREFS

Cf. A100678.

Sequence in context: A191761 A201451 A200352 * A201393 A327721 A327268

Adjacent sequences:  A286717 A286718 A286719 * A286721 A286722 A286723

KEYWORD

nonn

AUTHOR

Amiram Eldar, May 30 2017

STATUS

approved

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Last modified January 25 01:49 EST 2020. Contains 331229 sequences. (Running on oeis4.)