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A281532
a(n) = least numerator X such that the proper fraction X/A281529(n) needs n or more terms to be written as a signed sum of distinct unit fractions.
1
1, 2, 5, 18, 118
OFFSET
1,2
COMMENTS
Sierpiński conjectured that for any integer n > 3 there exist positive integers a, b, c so that 5/n = 1/a + 1/b + 1/c. If the conjecture is true, then 5 appears only once in the sequence.
REFERENCES
W. Sierpiński, O rozkładach liczb wymiernych na ułamki proste, PWN, Warsaw, Poland, 1957, pp. 96-100.
CROSSREFS
See A281529 for denominators.
Sequence in context: A058338 A006896 A125625 * A097584 A197855 A289126
KEYWORD
nonn,frac,hard,more
AUTHOR
STATUS
approved