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A243016
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Number of solutions for k*n/(k+n) = p for integer k > 0 and prime p.
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0
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0, 0, 1, 2, 0, 3, 0, 1, 0, 1, 0, 2, 0, 2, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 2, 0, 1, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1
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OFFSET
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1,4
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COMMENTS
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It is unknown whether a(6) = 3 is the highest number in this sequence.
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LINKS
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EXAMPLE
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4*k/(4+k) has two solutions: k=4,p=2 and k=12,p=3. Thus a(4) = 2.
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PROG
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(PARI) a(n) = {t=0; for(k=1, n*(n-1), s=k*n/(k+n); if(floor(s)==s, if(ispseudoprime(s), t+=1))); return(t); }
n=1; while(n<100, print1(a(n), ", "); n+=1)
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CROSSREFS
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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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