

A002967


Egyptian fractions: number of solutions of 1 = 1/x_1 + ... + 1/x_n in positive integers.
(Formerly M4745)


8




OFFSET

1,3


COMMENTS

Solutions differing only in the order of the x_i are counted as distinct.


REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, D11.
D. Singmaster, "The number of representations of one as a sum of unit fractions," unpublished manuscript, 1972.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS



EXAMPLE

For n=3 the 10 solutions are {2,3,6} (6 ways), {2,4,4} (3 ways), {3,3,3} (1 way).


CROSSREFS



KEYWORD

nonn,nice,hard,more


AUTHOR



EXTENSIONS

a(8) from John Dethridge, Jan 11 2004


STATUS

approved



