Star of David matchstick numbers: a(n) = 6*n*(3*n+1).

Terms

a(0) =0a(1) =24a(2) =84a(3) =180a(4) =312a(5) =480a(6) =684a(7) =924a(8) =1200a(9) =1512a(10) =1860a(11) =2244a(12) =2664a(13) =3120a(14) =3612a(15) =4140a(16) =4704a(17) =5304a(18) =5940a(19) =6612a(20) =7320a(21) =8064a(22) =8844a(23) =9660a(24) =10512a(25) =11400a(26) =12324a(27) =13284a(28) =14280a(29) =15312