Centered 18-gonal numbers.

Terms

a(0) =1a(1) =19a(2) =55a(3) =109a(4) =181a(5) =271a(6) =379a(7) =505a(8) =649a(9) =811a(10) =991a(11) =1189a(12) =1405a(13) =1639a(14) =1891a(15) =2161a(16) =2449a(17) =2755a(18) =3079a(19) =3421a(20) =3781a(21) =4159a(22) =4555a(23) =4969a(24) =5401a(25) =5851a(26) =6319a(27) =6805a(28) =7309a(29) =7831