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Number of unordered ways to write n as a sum of 3 odious numbers (A000069).
1

%I #8 Mar 30 2012 18:41:20

%S 0,0,1,1,1,2,1,1,2,3,2,3,3,2,4,6,5,5,6,5,6,8,8,9,9,8,10,12,12,14,14,

%T 10,14,19,14,18,20,14,19,25,21,20,27,22,23,32,26,27,31,29,31,36,35,35,

%U 39,34,38,47,40,42,47,40,43,60,53,44,60,50,48,68,62,54,64,65,58,75

%N Number of unordered ways to write n as a sum of 3 odious numbers (A000069).

%F a(n) = sum(i+j+k=n, A010060(i)*A010060(j)*A010060(k)) - _Benoit Cloitre_, Mar 19 2004

%o (PARI) a(n)=sum(i=1,n,sum(j=1,i,sum(k=1,j,if(i+j+k-n,0, A010060(i)*A010060(j)*A010060(k)))))

%Y Cf. A087916.

%Y Cf. A010060.

%K nonn,easy

%O 1,6

%A _Ralf Stephan_, Oct 18 2003