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A319337
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Filter sequence combining gcd(n,tau(n)) (= A009191) with the prime signature of n (A046523).
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3
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1, 2, 3, 4, 3, 5, 3, 6, 7, 5, 3, 8, 3, 5, 9, 10, 3, 8, 3, 11, 9, 5, 3, 12, 4, 5, 13, 11, 3, 14, 3, 15, 9, 5, 9, 16, 3, 5, 9, 12, 3, 14, 3, 11, 17, 5, 3, 18, 4, 11, 9, 11, 3, 19, 9, 12, 9, 5, 3, 20, 3, 5, 17, 21, 9, 14, 3, 11, 9, 14, 3, 22, 3, 5, 17, 11, 9, 14, 3, 23, 10, 5, 3, 20, 9, 5, 9, 12, 3, 24, 9, 11, 9, 5, 9, 25, 3, 11, 17, 26, 3, 14, 3, 12, 27
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OFFSET
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1,2
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COMMENTS
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Restricted growth sequence transform of ordered pair [A009191(n), A046523(n)].
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LINKS
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PROG
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(PARI)
up_to = 65537;
rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om, invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om, invec[i], i); outvec[i] = u; u++ )); outvec; };
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p=0); prod(i=1, #f, (p=nextprime(p+1))^f[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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