A186989 - OEIS

%I #7 Mar 30 2012 17:37:34

%S 1,2,4,4,12,4,28,16,32,12,110,16,209,46,69,98,507,57,828,141,277,193,

%T 1591,163,1289,413,1101,441,3785,163,5164,1479,1736,1187,2540,609,

%U 9561,1879,3086,1304,14298,738,18084,3322,3913,3888,25430

%N Number of subsets of {1, 2, ..., n} containing n and having <=5 pairwise coprime elements.

%H Alois P. Heinz, <a href="/A186989/b186989.txt">Table of n, a(n) for n = 1..200</a>

%e a(10) = 12 because there are 12 subsets of {1, 2, ..., 10} containing 10 and having <=5 pairwise coprime elements: {10}, {1,10}, {3,10}, {7,10}, {9,10}, {1,3,10}, {1,7,10}, {1,9,10}, {3,7,10}, {7,9,10}, {1,3,7,10}, {1,7,9,10}. There is no subset with exactly 5 elements here.

%Y Column 5 of triangle A186975. Sum of A186988 and A186976.

%K nonn

%O 1,2

%A _Alois P. Heinz_, Mar 03 2011