Number of n X n circulant singular (0,1) matrices over the reals.

Terms

a(0) =1a(1) =2a(2) =2a(3) =8a(4) =2a(5) =28a(6) =2a(7) =96a(8) =62a(9) =284a(10) =2a(11) =1504a(12) =2a(13) =3560a(14) =2738a(15) =16896a(16) =2a(17) =67636a(18) =2a(19) =235736a(20) =109334a(21) =707480a(22) =2a(23) =4376848a(24) =206282a(25) =10408792a(26) =5417630a(27) =48753784a(28) =2a(29) =212560504