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A228062
Numbers not expressible as a*b + b*c + a*c + 1 with positive numbers a, b, c.
0
1, 2, 3, 5, 7, 11, 19, 23, 31, 43, 59, 71, 79, 103, 131, 191, 211, 331, 463
OFFSET
1,2
COMMENTS
Except for the first term, all terms are prime. There is at most one more term.
MATHEMATICA
nn = 250; t = Select[Union[Flatten[Table[a*b + b*c + a*c + 1, {a, nn}, {b, a, nn}, {c, b, nn}]]], # <= 2*nn + 1 &]; Complement[Range[2*nn + 1], t]
CROSSREFS
Cf. A025052.
Sequence in context: A278694 A214837 A079346 * A332216 A059878 A105017
KEYWORD
nonn,fini
AUTHOR
T. D. Noe, Sep 13 2013
STATUS
approved