Column 6 of array illustrated in A089574 and related to A034261.

Terms

a(0) =7a(1) =71a(2) =350a(3) =1204a(4) =3329a(5) =7936a(6) =16981a(7) =33452a(8) =61719a(9) =107953a(10) =180620a(11) =291056a(12) =454129a(13) =688994a(14) =1019947a(15) =1477384a(16) =2098871a(17) =2930331a(18) =4027354a(19) =5456636a(20) =7297553a(21) =9643876a(22) =12605633a(23) =16311124a(24) =20909095a(25) =26571077a(26) =33493896a(27) =41902360a(28) =52052129