Main diagonal of A045847.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =5a(5) =21a(6) =61a(7) =141a(8) =309a(9) =766a(10) =2191a(11) =6436a(12) =18041a(13) =48348a(14) =128311a(15) =347166a(16) =960197a(17) =2674883a(18) =7413514a(19) =20411986a(20) =56130675a(21) =154907229a(22) =429349768a(23) =1192532452a(24) =3312339849a(25) =9196063371a(26) =25538113056a(27) =70994900341a(28) =197595884071a(29) =550414483911