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A290136 Positive numbers that are not the sum of two nonprime squarefree numbers (A000469). 1
1, 3, 4, 5, 6, 8, 9, 10, 13, 14, 17, 18, 19, 26, 33, 38, 46, 62, 82 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sequence is conjectured to be complete.

LINKS

Table of n, a(n) for n=1..19.

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]]

CROSSREFS

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

Sequence in context: A253897 A100966 A063977 * A332739 A306588 A219636

Adjacent sequences:  A290133 A290134 A290135 * A290137 A290138 A290139

KEYWORD

nonn,more

AUTHOR

Ilya Gutkovskiy, Jul 20 2017

STATUS

approved

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Last modified September 21 09:52 EDT 2021. Contains 347597 sequences. (Running on oeis4.)