a(n) = denominator of Atkin polynomials A_n(j) evaluated at j = 1728.

Terms

a(0) =1a(1) =1a(2) =5a(3) =1a(4) =1a(5) =1a(6) =13a(7) =5a(8) =17a(9) =17a(10) =1a(11) =1a(12) =25a(13) =5a(14) =29a(15) =29a(16) =29a(17) =5a(18) =37a(19) =481a(20) =1517a(21) =41a(22) =205a(23) =41a(24) =1a(25) =17a(26) =901a(27) =265a(28) =53a(29) =53