Denominators of Van der Pol numbers.

Terms

a(0) =1a(1) =2a(2) =5a(3) =20a(4) =350a(5) =140a(6) =1050a(7) =300a(8) =57750a(9) =38500a(10) =250250a(11) =45500a(12) =2388750a(13) =367500a(14) =318750a(15) =42500a(16) =1088106250a(17) =128012500a(18) =960093750a(19) =101062500a(20) =105761906250a(21) =10072562500a(22) =2289218750a(23) =199062500a(24) =8842968750a(25) =707437500a(26) =51289218750