

A069139


Egyptian fraction for square root of 1/2.


25



2, 5, 141, 68575, 32089377154, 1644444237306316731482, 65593236350142721999718859354569312622907814, 55836140966941396682452590821074724094286247680248793718758259857815239633935672711970868
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OFFSET

0,1


LINKS

Table of n, a(n) for n=0..7.
Index entries for sequences related to Egyptian fractions
Eric Weisstein's World of Mathematics, Egyptian Fraction


FORMULA

a(n) =ceiling[1/sqrt(2)Sum_i{i<n}1/a(i)]


EXAMPLE

a(3)=68575 since sqrt(1/2)=0.707106781186..., 1/2+1/5+1/141+1/68574=0.707106781368... (which is too much) and 1/2+1/5+1/141+1/68575=0.707106781155... (which is not too much).


MATHEMATICA

a = {}; k = N[1/Sqrt[2], 1000]; Do[s = Ceiling[1/k]; AppendTo[a, s]; k = k  1/s, {n, 1, 10}]; a [From Artur Jasinski, Sep 22 2008]


CROSSREFS

Cf. A006487.
Sequence in context: A145620 A130412 A175525 * A155762 A307480 A062611
Adjacent sequences: A069136 A069137 A069138 * A069140 A069141 A069142


KEYWORD

nonn


AUTHOR

Henry Bottomley, Apr 08 2002


STATUS

approved



