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A186891
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Numbers n such that the Stern polynomial B(n,x) is irreducible.
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30
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1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 53, 55, 59, 61, 65, 67, 71, 73, 77, 79, 83, 89, 91, 95, 97, 101, 103, 107, 109, 113, 115, 121, 125, 127, 131, 133, 137, 139, 143, 145, 149, 151, 157, 161, 163, 167, 169, 173, 175, 179, 181, 185, 191, 193, 197, 199
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OFFSET
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1,2
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COMMENTS
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Ulas and Ulas conjecture that all primes are here. The nonprime n are in A186892. See A186886 for the least number having n prime factors.
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LINKS
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FORMULA
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(End)
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MATHEMATICA
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ps[n_] := ps[n] = If[n<2, n, If[OddQ[n], ps[Quotient[n, 2]] + ps[Quotient[n, 2] + 1], x ps[Quotient[n, 2]]]];
selQ[n_] := IrreduciblePolynomialQ[ps[n]];
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PROG
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(PARI) ps(n)=if(n<2, n, if(n%2, ps(n\2)+ps(n\2+1), 'x*ps(n\2)))
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CROSSREFS
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Cf. A186892 (subsequence of nonprime terms).
Cf. A186893 (subsequence for self-reciprocal polynomials).
Cf. A283991 (characteristic function for terms > 1).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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