

A144063


Counting number of Egyptian fraction for 1 when the number of terms is given and the largest denominator is no more than 256.


0



1, 0, 1, 6, 62, 642, 5623, 47126, 368680, 2715613, 18876751, 124137535, 774232619, 4595291801, 26030660449, 141031079451, 731862267491, 3641135367129, 17379359388167, 79633646141291
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OFFSET

1,4


COMMENTS

Egyptian fraction for a rational number is to represent the number in sum of some distinct unit fraction, such as 1 = 1/2 + 1/3 + 1/6, here we represent 1 by a three terms Egyptian fraction and the largest denominator is 6. And the representation is nonunique.


LINKS

Table of n, a(n) for n=1..20.
Eric Weisstein's World of Mathematics, Egyptian Fraction
link for the result [Broken link]


EXAMPLE

a(1)=1 since 1=1/1 a(2)=0 since the sum of any two distinct unit fractions are not 1. a(3)=1 since the only three terms Egyptian fraction for 1 is 1/2+1/3+1/6 and the last nonzero term is a(114)=4, there are a total of 3007198863516917545589795267612 Egyptian fraction for 1 whose largest denominator is no more than 256.


CROSSREFS

Sequence in context: A243643 A200803 A198965 * A186670 A190726 A121251
Adjacent sequences: A144060 A144061 A144062 * A144064 A144065 A144066


KEYWORD

nonn,uned


AUTHOR

Zhao Hui Du, Sep 09 2008


STATUS

approved



