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.

A270358 Denominators of r-Egyptian fraction expansion for (1/2)^(1/3), where r = (1, 1/2, 1/4, 1/8, ...).

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%I A270358 #14 Feb 16 2025 08:33:31
%S A270358 2,2,6,62,3526,6487141,39385964848219,870200535339836766981506923,
%T A270358 7107112253865886739857942326428066600374758700504057908,
%U A270358 51149853017945104127158581151674618357470586573041429321297826264898103722100928190358789489996748918377200334
%N A270358 Denominators of r-Egyptian fraction expansion for (1/2)^(1/3), where r = (1, 1/2, 1/4, 1/8, ...).
%C A270358 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.
%C A270358 See A269993 for a guide to related sequences.
%H A270358 Clark Kimberling, <a href="/A270358/b270358.txt">Table of n, a(n) for n = 1..12</a>
%H A270358 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/EgyptianFraction.html">Egyptian Fraction</a>
%H A270358 <a href="/index/Ed#Egypt">Index entries for sequences related to Egyptian fractions</a>
%e A270358 (1/2)^(1/3) = 1/2 + 1/(2*2) + 1/(4*6) + ...
%t A270358 r[k_] := 2/2^k; f[x_, 0] = x; z = 10;
%t A270358 n[x_, k_] := n[x, k] = Ceiling[r[k]/f[x, k - 1]]
%t A270358 f[x_, k_] := f[x, k] = f[x, k - 1] - r[k]/n[x, k]
%t A270358 x = (1/2)^(1/3); Table[n[x, k], {k, 1, z}]
%Y A270358 Cf. A269993.
%K A270358 nonn,frac,easy
%O A270358 1,1
%A A270358 _Clark Kimberling_, Mar 20 2016