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A050252
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Number of digits in the prime factorization of n (counting terms of the form p^1 as p).
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7
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1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 2, 3, 3, 2, 4, 2, 3, 3, 3, 2, 3, 2, 4, 3, 3, 2, 3, 2, 3, 3, 4, 2, 3, 3, 3, 3, 3, 2, 4, 2, 3, 3, 2, 3, 4, 2, 4, 3, 3, 2, 4, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 2, 4, 3, 3, 3, 4, 2, 4, 3, 4, 3, 3, 3, 3, 2, 3, 4, 4, 3, 4
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| a(A192010(n)) = n and a(m) != n for m < A192010(n);
a(A046759(n))<A055642(A046759(n)); a(A046758(n))=A055642(A046758(n)); a(A046760(n))>A055642(A046760(n)). [Reinhard Zumkeller, Jun 21 2011]
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LINKS
| Eric Weisstein's World of Mathematics, Prime Factorization.
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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MATHEMATICA
| nd[n_]:=Total@IntegerLength@Select[Flatten@FactorInteger[n], #>1&]; Table[If[n==1, 1, nd[n]], {n, 102}] (* From Vladimir Joseph Stephan Orlovsky, Jan 30 2012 *)
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PROG
| (Haskell)
a050252 1 = 1
a050252 n = f n 0 where
f 1 x = x
f u x = g (u `div` spf) 1
where spf = a020639 u
g v e | r == 0 = g v' (e + 1)
| e == 1 = f v (x + a055642 spf)
| otherwise = f v (x + a055642 spf + a055642 e)
where (v', r) = divMod v spf
-- Reinhard Zumkeller, Jun 21 2011
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CROSSREFS
| Cf. A046758, A073048.
Cf. A055642, A020639, A027748, A110475.
Sequence in context: A008616 A097471 A025868 * A025877 A184171 A133989
Adjacent sequences: A050249 A050250 A050251 * A050253 A050254 A050255
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KEYWORD
| nonn,base
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AUTHOR
| Eric Weisstein (eric(AT)weisstein.com)
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