

A223938


Numbers n such that the trinomial x^nx1 is irreducible over GF(3).


2



2, 3, 4, 5, 6, 13, 14, 17, 30, 40, 41, 51, 54, 73, 121, 137, 364, 446, 485, 638, 925, 1382, 1478, 2211, 2726, 5581, 5678, 6424, 8524, 10649, 15990, 17174, 18685, 18889
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..34.


MATHEMATICA

Reap[ Do[ If[ Factor[x^n  x  1, Modulus > 3][[0]] =!= Times, Print[n]; Sow[n]], {n, 2, 3000}]][[2, 1]] (* JeanFrançois Alcover, Apr 03 2013 *)
Select[Range[1000], IrreduciblePolynomialQ[x^#  x  1, Modulus > 3] &] (* Robert Price, Sep 19 2018 *)


PROG

(Sage)
P.<x> = GF(3)[]
for n in range(10^6):
if (x^nx1).is_irreducible():
print(n)
(PARI)
for (n=1, 10^6, if ( polisirreducible(Mod(1, 3)*(x^nx1)), print1(n, ", ") ) );


CROSSREFS

Cf. A002475 (n such that x^nx1 is irreducible over GF(2)).
Sequence in context: A115307 A171597 A086185 * A222194 A057224 A153695
Adjacent sequences: A223935 A223936 A223937 * A223939 A223940 A223941


KEYWORD

nonn,more


AUTHOR

Joerg Arndt, Mar 29 2013


STATUS

approved



