a(n) = numerator(r(n)) where r(n) = Sum_{j=0..n} j!/(2^j*floor(j/2)!)^2.

A327494

a(n) = numerator(r(n)) where r(n) = Sum_{j=0..n} j!/(2^j*floor(j/2)!)^2.

Terms

    a(0) =1a(1) =5a(2) =11a(3) =47a(4) =191a(5) =779a(6) =1563a(7) =6287a(8) =50331a(9) =201639a(10) =403341a(11) =1614057a(12) =6456459a(13) =25828839a(14) =51658107a(15) =206638863a(16) =3306228243a(17) =13225022367a(18) =26450056889a(19) =105800458501a(20) =423201880193

External references