Numbers that are not the sum of 3 generalized 14-gonal numbers.
4, 5, 6, 7, 8, 9, 10, 17, 18, 19, 20, 21, 24, 27, 30, 31, 32, 37, 38, 43, 44, 47, 52, 55, 57, 58, 60, 63, 65, 66, 72, 75, 85, 86, 93, 95, 96, 99, 100, 105, 106, 113, 120, 123, 132, 133, 134, 135, 143, 148, 157, 158, 162, 167, 168, 171, 174, 180, 181, 182
1
This sequence begins slowly, but eventually becomes quadratic (or higher).
T. D. Noe, Plot of 1000 terms
T. D. Noe, Table of 1000 terms
Eric W. Weisstein, MathWorld: Polygonal Number
(Mma) f = 14; nn = 200; t = Table[k ((f - 2) k - (f - 4))/2, {k, -nn, nn}]; t2 = Select[Union[Flatten[Table[a + b + c, {a, t}, {b, t}, {c, t}]]], # <= t[[-1]] &]; Complement[Range[t[[-1]]], t2]
nonn
T. D. Noe, Dec 28 2015