This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A308220 #24 Jul 14 2019 13:37:35 %S A308220 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 A308220 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 A308220 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 A308220 Number of irreducible Egyptian fractions of denominator n which are the sum of 2 unit fractions. %H A308220 Cyril Banderier, Florian Luca, Francesco Pappalardi, <a href="https://lipn.fr/~cb/Papers/EgyptianFractions.pdf">Numerators of Egyptian fractions</a>, 2019. %F A308220 For p prime, a(p) = number_of_divisors(p+1). %e A308220 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 A308220 Cf. A308219, A308221, A308415. %K A308220 nonn %O A308220 1,1 %A A308220 _Cyril Banderier_, May 15 2019