6 times centered hexagonal numbers: 18*n*(n+1) + 6.

Terms

a(0) =6a(1) =42a(2) =114a(3) =222a(4) =366a(5) =546a(6) =762a(7) =1014a(8) =1302a(9) =1626a(10) =1986a(11) =2382a(12) =2814a(13) =3282a(14) =3786a(15) =4326a(16) =4902a(17) =5514a(18) =6162a(19) =6846a(20) =7566a(21) =8322a(22) =9114a(23) =9942a(24) =10806a(25) =11706a(26) =12642a(27) =13614a(28) =14622a(29) =15666