Denominators associated with A109139.

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =31a(5) =69a(6) =307a(7) =683a(8) =3039a(9) =18917a(10) =40873a(11) =264155a(12) =1097493a(13) =2459141a(14) =10934057a(15) =68063483a(16) =419314955a(17) =906693393a(18) =5859475313a(19) =24344594645a(20) =54548664603a(21) =351636582263