a(n) = numerator(r(n)) where r(n) = (n/2)*(Pi/2)^cos(Pi*(n-1))*((n/2-1/2)!/(n/2)!)^2.

A380949

a(n) = numerator(r(n)) where r(n) = (n/2)*(Pi/2)^cos(Pi*(n-1))*((n/2-1/2)!/(n/2)!)^2.

Terms

    a(0) =0a(1) =1a(2) =1a(3) =4a(4) =9a(5) =64a(6) =75a(7) =256a(8) =1225a(9) =16384a(10) =19845a(11) =65536a(12) =160083a(13) =1048576a(14) =1288287a(15) =4194304a(16) =41409225a(17) =1073741824a(18) =1329696225a(19) =4294967296a(20) =10667118605a(21) =68719476736a(22) =85530896451a(23) =274877906944

External references