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A207967 Numbers that match non-irreducible polynomials over {0,1,2}; complement of A207966. 3
1, 2, 9, 12, 15, 16, 18, 21, 24, 27, 28, 30, 32, 33, 36, 39, 40, 42, 44, 45, 48, 50, 51, 52, 54, 56, 57, 60, 63, 64, 66, 68, 69, 70, 72, 75, 76, 78, 80, 81, 84, 87, 88, 90, 91, 93, 96, 99, 100, 102, 104, 105, 108, 111, 112, 114, 116, 117, 119, 120, 123, 124 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A207966.

LINKS

Table of n, a(n) for n=1..62.

EXAMPLE

(See A207966.)

MATHEMATICA

t = Table[IntegerDigits[n, 3], {n, 1, 850}];

b[n_] := Reverse[Table[x^k, {k, 0, n}]]

p[n_, x_] := t[[n]].b[-1 + Length[t[[n]]]]

Table[p[n, x], {n, 1, 15}]

u = {}; Do[n++; If[IrreduciblePolynomialQ[p[n, x]],

  AppendTo[u, n]], {n, 300}]; u  (* A207966 *)

Complement[Range[200], u]        (* A207967 *)

b[n_] := FromDigits[IntegerDigits[u, 3][[n]]]

Table[b[n], {n, 1, 50}]          (* A207968 *)

CROSSREFS

Cf. A207966, A207968.

Sequence in context: A030376 A080520 A032372 * A265413 A297830 A103008

Adjacent sequences:  A207964 A207965 A207966 * A207968 A207969 A207970

KEYWORD

nonn

AUTHOR

Clark Kimberling, Feb 21 2012

STATUS

approved

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Last modified December 7 16:53 EST 2021. Contains 349581 sequences. (Running on oeis4.)