Odd 10-gonal (or decagonal) numbers.

Terms

a(0) =1a(1) =27a(2) =85a(3) =175a(4) =297a(5) =451a(6) =637a(7) =855a(8) =1105a(9) =1387a(10) =1701a(11) =2047a(12) =2425a(13) =2835a(14) =3277a(15) =3751a(16) =4257a(17) =4795a(18) =5365a(19) =5967a(20) =6601a(21) =7267a(22) =7965a(23) =8695a(24) =9457a(25) =10251a(26) =11077a(27) =11935a(28) =12825a(29) =13747