A168078 - OEIS

%I #5 Mar 30 2012 17:35:31

%S 1,4,12,32,144,176,1728,4320,27936

%N Number of matrices with elements 1..n in which every pair of adjacent elements are relatively prime

%C For prime p, a(p) = 2*A076220(p)

%H Lior Manor, <a href="/A168078/a168078.gif">Illustration of initial terms</a>

%Y Cf. A000005, A076220

%K more,nonn

%O 1,2

%A _Lior Manor_, Nov 18 2009