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A228122
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Smallest nonnegative number x such that x^2 + x + 41 has exactly n prime factors counting multiplicities.
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4
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(1) = 0 because if x = 0 then x^2 + x + 41 = 41, which has 1 prime factor.
a(2) = 40 because if x = 40 then x^2 + x + 41 = 1681 = 41*41, which has 2 prime factors, counting multiplicities.
a(3) = 420 because if x = 420 then x^2 + x + 41 = 176861 = 47*53*71, which has 3 prime factors.
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MATHEMATICA
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a = {}; Do[x = 0; While[PrimeOmega[x^2 + x + 41] != k, x++]; AppendTo[a, x], {k, 9}]; a
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PROG
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(PARI) a(n) = {my(m=0); while (bigomega(m^2+m+41) != n, m++); m; } \\ Michel Marcus, Jan 31 2016
(Python)
from sympy import factorint
k = 0
while sum(factorint(k*(k+1)+41).values()) != n:
k += 1
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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