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A270001 Denominators of r-Egyptian fraction expansion for 1/e, where r = (1,1/2,1/3,1/4,...) 2
3, 15, 275, 382677, 1046649251798, 2422932913436254796909358, 7298956212857760367589586285406004970615840077289, 146254918268677439622519920044753993861333975570554456887622664610038423045957554361330873143236585 (list; graph; refs; listen; history; text; internal format)
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

1/e = 1/3 + 1/(2*15) + 1/(3*275) + ...

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 = 1/E; Table[n[x, k], {k, 1, z}]

CROSSREFS

Cf. A269993.

Sequence in context: A013356 A013353 A270401 * A138896 A090627 A070234

Adjacent sequences:  A269998 A269999 A270000 * A270002 A270003 A270004

KEYWORD

nonn,frac,easy

AUTHOR

Clark Kimberling, Mar 15 2016

STATUS

approved

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Last modified January 19 06:37 EST 2020. Contains 331033 sequences. (Running on oeis4.)