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A257568
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The least prime p such that the highest power of 3 that divides p^2 + 2 is n.
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2
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3, 2, 13, 5, 59, 751, 1237, 6053, 10427, 36671, 1532579, 351599, 356989, 12048691, 105931211, 96365273, 190612867, 18425983, 1014695321, 8763105101, 20385719771, 7508555437, 97094976593, 1911292838383, 22999364895631, 46158586887073, 6373306898393
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OFFSET
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0,1
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LINKS
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EXAMPLE
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a(0) = 3 because 3^2+2=11 not divisible by 3,
a(18) = 1014695321 because 1014695321^2+2 = 3^18*2657594587,
a(21) = 7508555437 because 7508555437^2+2 = 3^21*17*317042521.
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PROG
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(PARI) a(n)=if(n==1, return(2)); my(k=3^n, m=1, p); while(!issquare(m*k-2, &p) || !isprime(p), m+=2; if(m%3==0, m+=2)); p \\ Charles R Greathouse IV, May 01 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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