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A309747
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Numbers k such that k^k + (k+1)^(k+1) is a semiprime.
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0
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5, 7, 9, 11, 14, 21, 37, 38, 39, 57, 90, 97, 162
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OFFSET
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1,1
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COMMENTS
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Numbers k such that A217435(k+1) = 2.
a(14) >= 235, see FactorDB link.
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LINKS
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EXAMPLE
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a(1) = 5 because 5^5 + 6^6 = 49781 = 67*743.
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PROG
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(PARI) for(k=0, 40, if(bigomega(k^k+(k+1)^(k+1))==2, print1(k, ", ")))
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CROSSREFS
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KEYWORD
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nonn,more,hard
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AUTHOR
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STATUS
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approved
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