Fourth column of A046741.

Terms

a(0) =3a(1) =26a(2) =94a(3) =234a(4) =473a(5) =838a(6) =1356a(7) =2054a(8) =2959a(9) =4098a(10) =5498a(11) =7186a(12) =9189a(13) =11534a(14) =14248a(15) =17358a(16) =20891a(17) =24874a(18) =29334a(19) =34298a(20) =39793a(21) =45846a(22) =52484a(23) =59734a(24) =67623a(25) =76178a(26) =85426a(27) =95394a(28) =106109a(29) =117598