Triangular array related to tennis ball problem, read by rows.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =4a(6) =10a(7) =16a(8) =13a(9) =6a(10) =31a(11) =47a(12) =45a(13) =25a(14) =8a(15) =105a(16) =158a(17) =145a(18) =96a(19) =41a(20) =10a(21) =343a(22) =501a(23) =500a(24) =340a(25) =175a(26) =61a(27) =12a(28) =1198a(29) =1752