First trisection of A061037 (Balmer line series of the hydrogen atom).

Terms

a(0) =0a(1) =21a(2) =15a(3) =117a(4) =12a(5) =285a(6) =99a(7) =525a(8) =42a(9) =837a(10) =255a(11) =1221a(12) =90a(13) =1677a(14) =483a(15) =2205a(16) =156a(17) =2805a(18) =783a(19) =3477a(20) =240a(21) =4221a(22) =1155a(23) =5037a(24) =342a(25) =5925a(26) =1599a(27) =6885a(28) =462a(29) =7917