a(n) = (A262026(n) - 1)/2.

Terms

a(0) =0a(1) =1a(2) =0a(3) =1a(4) =0a(5) =19a(6) =2a(7) =0a(8) =2a(9) =136a(10) =1a(11) =0a(12) =1a(13) =265a(14) =3a(15) =0a(16) =3a(17) =34a(18) =0a(19) =2983a(20) =206a(21) =1a(22) =4a(23) =0a(24) =4a(25) =1a(26) =10a(27) =82a(28) =2a(29) =0