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A331287
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a(n) = gcd(n, A225546(n)).
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7
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1, 2, 1, 1, 1, 2, 1, 2, 9, 2, 1, 12, 1, 2, 1, 1, 1, 18, 1, 4, 1, 2, 1, 24, 1, 2, 9, 4, 1, 2, 1, 2, 1, 2, 1, 9, 1, 2, 1, 8, 1, 2, 1, 4, 9, 2, 1, 4, 1, 2, 1, 4, 1, 18, 1, 8, 1, 2, 1, 12, 1, 2, 9, 1, 1, 2, 1, 4, 1, 2, 1, 18, 1, 2, 3, 4, 1, 2, 1, 80, 1, 2, 1, 12, 1, 2, 1, 8, 1, 18, 1, 4, 1, 2, 1, 8, 1, 2, 9, 1, 1, 2, 1, 8, 1
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OFFSET
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1,2
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LINKS
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FORMULA
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PROG
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(PARI)
A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; };
A331287(n) = if(1==n, 1, my(f=factor(n), u=#binary(vecmax(f[, 2])), prods=vector(u, x, 1), m=1, e); for(i=1, u, if(!(n%prime(i)), for(k=1, #f~, if(bitand(f[k, 2], m), prods[i] *= f[k, 1]))); m<<=1); prod(i=1, u, prime(i)^min(valuation(n, prime(i)), A048675(prods[i]))));
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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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