Maximal number of 4-tree rows in n-tree orchard problem.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =1a(6) =2a(7) =2a(8) =3a(9) =5a(10) =6a(11) =7a(12) =9a(13) =10a(14) =12a(15) =15a(16) =16a(17) =18a(18) =20a(19) =23