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A257841
z-value of the lexicographically first solution (x,y,z) of 4/n = 1/x + 1/y + 1/z with 0 < x < y < z all integers, or 0 if there is no such solution. Corresponding x and y values are in A257839 and A257840.
5
0, 0, 12, 6, 20, 42, 210, 42, 90, 240, 1122, 156, 468, 812, 3660, 420, 510, 2070, 9120, 930, 1806, 4422, 19182, 1806, 2100, 8372, 35910, 3192, 9048, 14520, 61752, 5256, 9900, 23562, 99540, 8190, 22940, 36290, 152490, 12210, 6314, 53592, 224202, 17556, 32580, 76452, 318660, 24492, 9702, 105950, 440232, 33306, 92008, 143262, 593670, 44310, 81510, 189660, 784110, 57840
OFFSET
1,3
COMMENTS
See A073101 for more details.
This differs from A075247 starting with a(89) = 61410 vs. A075247(89) = 108936, corresponding to the representations 4/89 = 1/23 + 1/690 + 1/61410 = 1/24 + 1/306 + 1/108936.
LINKS
PROG
(PARI) apply( {A257841(n, t)=for(x=n\4+1, 3*n\4, for(y=max(1\t=4/n-1/x, x)+1, ceil(2/t)-1, numerator(t-1/y)==1 && return(y/(t*y-1))))}, [1..99]) \\ improved by M. F. Hasler, Jul 03 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, May 16 2015
STATUS
approved