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 A057489 Numbers n > 13 such that x^n + x^13 + x^12 + x^11 + x^10 + x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x + 1 is irreducible over GF(2). 0
 15, 21, 25, 42, 43, 48, 60, 97, 106, 133, 147, 148, 178, 201, 252, 253, 327, 513, 570, 732, 763, 1108, 1342, 1572, 2175, 2407, 2605, 2850, 3930, 4627, 6181, 6312, 7048, 7596, 8995, 9250, 9873, 11841, 12471, 13927, 20658, 20965, 33957, 72373, 91992, 156657 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS No terms == 2 mod 3 or == 4 mod 5. - Robert Israel, Feb 22 2017 LINKS Table of n, a(n) for n=1..46. MAPLE Q:= add(x^i, i=0..13): select(t -> Irreduc(x^t+Q) mod 2, [\$14..1000]); # Robert Israel, Feb 22 2017 PROG (PARI) isok(n) = (n>13) && polisirreducible(Mod(1, 2)*(x^n+sum(k=0, 13, x^k))); \\ Michel Marcus, Feb 23 2017 CROSSREFS Sequence in context: A129926 A020204 A280389 * A070811 A211375 A326387 Adjacent sequences: A057486 A057487 A057488 * A057490 A057491 A057492 KEYWORD nonn AUTHOR Robert G. Wilson v, Sep 28 2000 EXTENSIONS a(22)-a(24) from Robert Israel, Feb 22 2017 a(25)-a(32) from Jinyuan Wang, Apr 15 2020 a(33)-a(47) from Lucas A. Brown, Nov 29 2022 STATUS approved

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Last modified June 25 02:10 EDT 2024. Contains 373691 sequences. (Running on oeis4.)