Reverse binary expansion of the factorial numbers.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =3a(5) =15a(6) =45a(7) =441a(8) =441a(9) =3213a(10) =16059a(11) =172569a(12) =517671a(13) =6695325a(14) =43746885a(15) =903732249a(16) =903732249a(17) =14611840389a(18) =110769926061