Zagier's function J_1(4*n).

Terms

a(0) =2a(1) =492a(2) =7256a(3) =53008a(4) =287244a(5) =1262512a(6) =4833456a(7) =16576512a(8) =52255768a(9) =153541020a(10) =425691312a(11) =1122626864a(12) =2835861520a(13) =6896878512a(14) =16220381536a(15) =37017882624a(16) =82226601996a(17) =178211037024a(18) =377674773768a(19) =784073551152