A290136 Positive numbers that are not the sum of two nonprime squarefree numbers (A000469).

1, 3, 4, 5, 6, 8, 9, 10, 13, 14, 17, 18, 19, 26, 33, 38, 46, 62, 82

Offset: 1

Author

Ilya Gutkovskiy, Jul 20 2017

Keywords

• nonn
• more

Comments

The sequence is conjectured to be complete.

Crossrefs

Cf. A000469, A014092, A071068, A071331, A098235, A239508, A239509.

Programs

Mathematica

nmax = 82; f[x_] := Sum[Boole[SquareFreeQ[k] && PrimeNu[k] != 1] x^k, {k, 1, nmax}]^2; b = Exponent[#, x] & /@ List @@ Normal[Series[f[x], {x, 0, nmax}]]; c = Complement[Range[nmax], b][[1 ;; 19]]