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%I #24 Jul 14 2019 13:37:35
%S 2,2,3,3,4,3,4,4,5,4,6,4,4,5,5,5,6,5,6,6,8,4,8,6,6,7,8,7,8,6,6,7,7,7,
%T 10,7,4,7,11,8,8,7,6,8,9,5,10,9,8,9,9,9,8,7,12,9,10,6,12,9,4,8,11,9,
%U 12,9,6,10,12,8,12,10,4,9,13,10,13,7,10,11,10,6,12,12,10,9,12,10,12,10,10,9,10,7,12,11,6,11,13,12
%N Number of irreducible Egyptian fractions of denominator n which are the sum of 2 unit fractions.
%H Cyril Banderier, Florian Luca, Francesco Pappalardi, <a href="https://lipn.fr/~cb/Papers/EgyptianFractions.pdf">Numerators of Egyptian fractions</a>, 2019.
%F For p prime, a(p) = number_of_divisors(p+1).
%e There are a(2)=2 irreducible fractions with denominator n=2 which are sums of 2 unit fractions: 1/2 = 1/4 + 1/4 and 3/2 = 1/1 + 1/2.
%Y Cf. A308219, A308221, A308415.
%K nonn
%O 1,1
%A _Cyril Banderier_, May 15 2019