OFFSET
1,2
COMMENTS
Erdős and Straus conjectured that for all integers n >= 2, the rational number 4/n can be expressed as an Egyptian fraction with exactly three unit fractions -- that is, 4/n = 1/x + 1/y + 1/z where x, y and z are positive integers. The conjecture has been verified to high values of n, and Mordell has provided formulas to compute x, y and z for many n. The values of n NOT included in Mordell's formulas are those for which n modulo 840 = {an element of this sequence}. Each element is the square of a prime.
REFERENCES
Louis J. Mordell, Diophantine Equations, Academic Press, 1967, 287-290.
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Kenneth Vollmar, Apr 12 2014
STATUS
approved