A270314 Denominators of r-Egyptian fraction expansion for log(2), where r = (1,1/2,1/3,1/4,...).

2, 3, 13, 298, 355823, 306479173303, 85372761970827958806466, 16575976283809775714654644103484953548013865676, 269025959411335919672976939610798847100114463059537709191005089031919232139117472577538965440

Offset

1,1

Comments

Suppose that r is a sequence of rational numbers r(k) <= 1 for k >= 1, and that x is an irrational number in (0,1). Let f(0) = x, n(k) = floor(r(k)/f(k-1)), and f(k) = f(k-1) - r(k)/n(k). Then x = r(1)/n(1) + r(2)/n(2) + r(3)/n(3) + ... , the r-Egyptian fraction for x.

See A269993 for a guide to related sequences.

Links

Clark Kimberling, Table of n, a(n) for n = 1..12

Eric Weisstein's World of Mathematics, Egyptian Fraction

Index entries for sequences related to Egyptian fractions

Example

log(2) = 1/2 + 1/(2*3) + 1/(3*13) + ...

Mathematica

r[k_] := 1/k; f[x_, 0] = x; z = 10;
n[x_, k_] := n[x, k] = Ceiling[r[k]/f[x, k - 1]]
f[x_, k_] := f[x, k] = f[x, k - 1] - r[k]/n[x, k]
x = Log[2]; Table[n[x, k], {k, 1, z}]

Crossrefs

Cf. A269993.

Sequence in context: A119564 A132358 A090100 * A132484 A258357 A160858

Adjacent sequences: A270311 A270312 A270313 * A270315 A270316 A270317

Keyword

nonn,frac,easy

Author

Clark Kimberling, Mar 15 2016

Status

approved