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A137795
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Smallest positive m such that m*n is free of prime gaps in canonical factorization.
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4
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1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 15, 1, 1, 1, 1, 1, 3, 5, 105, 1, 1, 1, 1155, 1, 15, 1, 1, 1, 1, 35, 15015, 1, 1, 1, 255255, 385, 3, 1, 5, 1, 105, 1, 4849845, 1, 1, 1, 3, 5005, 1155, 1, 1, 7, 15, 85085, 111546435, 1, 1, 1, 3234846615, 5, 1, 77, 35, 1, 15015, 1616615, 3, 1, 1
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OFFSET
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1,10
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LINKS
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FORMULA
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EXAMPLE
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the gap is filled by a(42) = 5: A073490(42*5) = 0.
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PROG
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(PARI) A137795(n) = if(1==n, 1, my(f = factor(n), p = f[1, 1], gpf = f[#f~, 1], m = 1); while(p<gpf, if((n%p), m*=p); p = nextprime(1+p)); (m)); \\ Antti Karttunen, Sep 06 2018
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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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