Subtract 1 from Pascal's triangle, read by rows.

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =5a(5) =3a(6) =4a(7) =9a(8) =9a(9) =4a(10) =5a(11) =14a(12) =19a(13) =14a(14) =5a(15) =6a(16) =20a(17) =34a(18) =34a(19) =20a(20) =6a(21) =7a(22) =27a(23) =55a(24) =69a(25) =55a(26) =27a(27) =7a(28) =8a(29) =35