A186984 - OEIS

%I #8 Mar 30 2012 17:37:34

%S 8,8,73,75,79,81,420,428,719,750,1014,1056,3632,3640,10167,11603,

%T 12570,13180,14698,14930,36325,38118,41241,42243,92553,93093,186945,

%U 195339,203985,213681,401403,407475,549417,563277,608091,633633,1106226

%N Number of 8-element subsets of {1, 2, ..., n} having pairwise coprime elements.

%H Alois P. Heinz, <a href="/A186984/b186984.txt">Table of n, a(n) for n = 17..200</a>

%e a(17) = 8 because there are 8 8-element subsets of {1, 2, ..., 17} having pairwise coprime elements: {1,2,3,5,7,11,13,17}, {1,2,5,7,9,11,13,17}, {1,3,4,5,7,11,13,17}, {1,3,5,7,8,11,13,17}, {1,3,5,7,11,13,16,17}, {1,4,5,7,9,11,13,17}, {1,5,7,9,11,13,16,17}, {1,5,7,8,9,11,13,17}.

%Y Column 8 of triangle A186974. Partial sums of A186979.

%K nonn

%O 17,1

%A _Alois P. Heinz_, Mar 02 2011