Sums of three consecutive heptagonal numbers.

Terms

a(0) =8a(1) =26a(2) =59a(3) =107a(4) =170a(5) =248a(6) =341a(7) =449a(8) =572a(9) =710a(10) =863a(11) =1031a(12) =1214a(13) =1412a(14) =1625a(15) =1853a(16) =2096a(17) =2354a(18) =2627a(19) =2915a(20) =3218a(21) =3536a(22) =3869a(23) =4217a(24) =4580a(25) =4958a(26) =5351a(27) =5759a(28) =6182a(29) =6620