Conjectured number of numbers that are not the sum of three n-gonal numbers, or -1 if infinite.

Terms

a(0) =0a(1) =-1a(2) =210a(3) =638a(4) =1348a(5) =-1a(6) =5282a(7) =7687a(8) =12453a(9) =-1a(10) =24813a(11) =-1a(12) =45338a(13) =-1a(14) =63702a(15) =84764a(16) =109613a(17) =-1a(18) =162687a(19) =155879a(20) =224244a(21) =-1a(22) =303049a(23) =-1a(24) =353690a(25) =-1a(26) =522262a(27) =541796a(28) =651844a(29) =-1