Structured hexagonal diamond numbers (vertex structure 5).

Terms

a(0) =1a(1) =8a(2) =29a(3) =72a(4) =145a(5) =256a(6) =413a(7) =624a(8) =897a(9) =1240a(10) =1661a(11) =2168a(12) =2769a(13) =3472a(14) =4285a(15) =5216a(16) =6273a(17) =7464a(18) =8797a(19) =10280a(20) =11921a(21) =13728a(22) =15709a(23) =17872a(24) =20225a(25) =22776a(26) =25533a(27) =28504a(28) =31697a(29) =35120