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A103893
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Number of distinct prime factors of prime(n)! / prime(n)# + 1.
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2
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1, 1, 1, 1, 2, 3, 3, 4, 2, 3, 2, 4, 4, 5, 3, 2, 3, 4, 6, 5, 5, 5, 5, 6, 5, 4, 5, 3, 7, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,5
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COMMENTS
| Also the number of distinct prime factors of the P_n-th compositorial.
a(n) = A001221(A103890(n)).
a(31)>4 and its composite part is a 155-digit number.
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LINKS
| Dario Alejandro Alpern, Factorization using the Elliptic Curve Method
Hisanori Mishimar, Compositorial + 1 (n = 4 to 150)
R. Zumkeller, p(n)!/p(n )#+1
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MATHEMATICA
| bigomega[n_Integer] := Plus @@ Last /@ FactorInteger[n]; f[n_] := Prime[n]!/Product[Prime[i], {i, n}] + 1; Table[ f[n], {n, 27}] (from Robert G. Wilson v Mar 11 2005)
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CROSSREFS
| Cf. A103858.
Sequence in context: A177876 A079633 A060573 * A106448 A159909 A176004
Adjacent sequences: A103890 A103891 A103892 * A103894 A103895 A103896
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 20 2005
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EXTENSIONS
| Corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 12 2005
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