Number of nodes in virtual, "optimal", chordal graphs of diameter 4 and degree n+1.

Terms

a(0) =9a(1) =16a(2) =41a(3) =66a(4) =129a(5) =192a(6) =321a(7) =450a(8) =681a(9) =912a(10) =1289a(11) =1666a(12) =2241a(13) =2816a(14) =3649a(15) =4482a(16) =5641a(17) =6800a(18) =8361a(19) =9922a(20) =11969a(21) =14016a(22) =16641a(23) =19266a(24) =22569a(25) =25872a(26) =29961a(27) =34050a(28) =39041a(29) =44032