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A106490
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Total number of bases and exponents in Quetian Superfactorization of n, excluding the unity-exponents at the tips of branches.
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15
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0, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 3, 2, 2, 2, 3, 1, 3, 1, 2, 2, 2, 2, 4, 1, 2, 2, 3, 1, 3, 1, 3, 3, 2, 1, 4, 2, 3, 2, 3, 1, 3, 2, 3, 2, 2, 1, 4, 1, 2, 3, 3, 2, 3, 1, 3, 2, 3, 1, 4, 1, 2, 3, 3, 2, 3, 1, 4, 3, 2, 1, 4, 2, 2, 2, 3, 1, 4, 2, 3, 2, 2, 2, 3, 1, 3, 3, 4, 1, 3
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OFFSET
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1,4
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COMMENTS
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Quetian Superfactorization proceeds by factoring a natural number to its unique prime-exponent factorization (p1^e1 * p2^e2 * ... pj^ej) and then factoring recursively each of the (nonzero) exponents in similar manner, until unity-exponents are finally encountered.
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LINKS
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FORMULA
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Additive with a(p^e) = 1 + a(e).
Other identities. For all n >= 1:
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EXAMPLE
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a(64) = 3, as 64 = 2^6 = 2^(2^1*3^1) and there are three non-1 nodes in that superfactorization. Similarly, for 360 = 2^(3^1) * 3^(2^1) * 5^1 we get a(360) = 5. a(65536) = a(2^(2^(2^(2^1)))) = 4.
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MAPLE
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a:= proc(n) option remember; `if`(n=1, 0,
add(1+a(i[2]), i=ifactors(n)[2]))
end:
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MATHEMATICA
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PROG
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(Scheme, with memoization-macro definec)
(PARI)
A067029(n) = if(n<2, 0, factor(n)[1, 2]);
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CROSSREFS
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Cf. A276230 (gives first k such that a(k) = n, i.e., this sequence is a left inverse of A276230).
After n=1 differs from A038548 for the first time at n=24, where A038548(24)=4, while a(24)=3.
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KEYWORD
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nonn
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AUTHOR
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Antti Karttunen, May 09 2005 based on Leroy Quet's message ('Super-Factoring' An Integer) posted to SeqFan-mailing list on Dec 06 2003.
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STATUS
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approved
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