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%I #12 Oct 31 2017 18:10:49
%S 0,2,5,26,77,87,223,962,4609,4861,55991,58301,785633,811373,835397,
%T 3431678,29889983,30570663,197698279,201578155,41054655,13920029,
%U 325333835,990874363,25128807667,25472027467,232222818803,235091155703
%N Numerator of the Harary number for the path graph P_n.
%H Andrew Howroyd, <a href="/A160048/b160048.txt">Table of n, a(n) for n = 1..200</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/HararyIndex.html">Harary Index</a>
%e 0, 2, 5, 26/3, 77/6, 87/5, 223/10, 962/35, 4609/140, 4861/126, ...
%o (PARI)
%o harmonic(n)=sum(k=1,n,1/k);
%o a(n)=numerator(2*n*(harmonic(n)-1)); \\ _Andrew Howroyd_, Oct 31 2017
%Y Cf. A160049, A027612.
%K nonn,frac
%O 1,2
%A _Eric W. Weisstein_, Apr 30 2009
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