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A281531 a(n) = least numerator k such that the proper fraction k/n needs three or more terms as an Egyptian fraction, or 0 if no such numerator exists. 0
0, 0, 0, 4, 0, 3, 7, 7, 8, 5, 11, 3, 6, 7, 7, 4, 13, 3, 13, 9, 5, 5, 17, 4, 6, 8, 12, 4, 14, 3, 7, 5, 8, 11, 17, 3, 6, 9, 17, 4, 18, 3, 7, 11, 7, 5, 21, 3, 8, 7, 11, 4, 13, 9, 13, 7, 7, 7, 28, 3, 5, 13, 7, 4, 10, 3, 11, 11, 13, 5, 23, 3, 6, 11, 9, 5, 11, 3, 19 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,4

LINKS

Table of n, a(n) for n=2..80.

Index entries for sequences related to Egyptian fractions

PROG

(MAGMA) lst:=[]; for n in [2..80] do for k in [1..n-1] do f:=k/n; x:=1; v:=0; if Numerator(f) eq 1 then v:=1; else while f lt 2/x do if Numerator(f-1/x) eq 1 then v:=1; break; end if; x+:=1; end while; end if; if v eq 0 then Append(~lst, k); break; end if; if k eq n-1 then Append(~lst, 0); end if; end for; end for; lst;

CROSSREFS

Cf. A281530.

Sequence in context: A062525 A085655 A153615 * A248914 A246686 A048649

Adjacent sequences:  A281528 A281529 A281530 * A281532 A281533 A281534

KEYWORD

nonn

AUTHOR

Arkadiusz Wesolowski, Jan 23 2017

STATUS

approved

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Last modified August 25 10:20 EDT 2019. Contains 326324 sequences. (Running on oeis4.)