Number of 3-element subsets that can be chosen from {1,2,...,6*n+3} having element sum 9*n+6.

Terms

a(0) =1a(1) =8a(2) =25a(3) =50a(4) =85a(5) =128a(6) =181a(7) =242a(8) =313a(9) =392a(10) =481a(11) =578a(12) =685a(13) =800a(14) =925a(15) =1058a(16) =1201a(17) =1352a(18) =1513a(19) =1682a(20) =1861a(21) =2048a(22) =2245a(23) =2450a(24) =2665a(25) =2888a(26) =3121a(27) =3362a(28) =3613a(29) =3872