a(n)=a(n-1)+a(n-2)+a(n-3), a(0)=3, a(1)=1, a(2)=3. 3, 1, 3, 7, 11, 21, 39, 71, 131, 241, 443, 815, 1499, 2757, 5071, 9327, 17155, 31553
1 seqfan posts