Number of convex polygons on the lines of a triangular grid with edge length n.

Terms

a(0) =1a(1) =11a(2) =50a(3) =157a(4) =398a(5) =876a(6) =1742a(7) =3208a(8) =5561a(9) =9179a(10) =14548a(11) =22281a(12) =33138a(13) =48048a(14) =68132a(15) =94728a(16) =129417a(17) =174051a(18) =230782a(19) =302093a(20) =390830a(21) =500236a(22) =633986a(23) =796224a(24) =991601a(25) =1225315a(26) =1503152a(27) =1831529a(28) =2217538a(29) =2668992