a(n) = 1 + Sum_{d|n, d < n} a(d)^2.

Terms

a(0) =1a(1) =2a(2) =2a(3) =6a(4) =2a(5) =10a(6) =2a(7) =42a(8) =6a(9) =10a(10) =2a(11) =146a(12) =2a(13) =10a(14) =10a(15) =1806a(16) =2a(17) =146a(18) =2a(19) =146a(20) =10a(21) =10a(22) =2a(23) =23226a(24) =6a(25) =10a(26) =42a(27) =146a(28) =2a(29) =314