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Search: id:A073919
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| A073919 |
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Smallest prime p with bigomega(p-1)=n, where bigomega(m)=A001222(m) is the number of prime divisors of m (counted with multiplicity). |
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+0
3
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| 2, 3, 5, 13, 17, 73, 97, 193, 257, 769, 3457, 7681, 15361, 12289, 40961, 114689, 65537, 737281, 1376257, 786433, 5308417, 7340033, 14155777, 28311553, 104857601, 113246209, 167772161, 469762049, 2113929217, 1811939329
(list; graph; listen)
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OFFSET
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0,1
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EXAMPLE
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a(2) = 5 = 2*2 + 1. a(5) = 73 = 2*2*2*3*3 + 1.
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MATHEMATICA
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ptns[n_, 0] := If[n==0, {{}}, {}]; ptns[n_, k_] := Module[{r}, If[n<k, Return[{}]]; ptns[n, k]=1+Union@@Table[PadRight[ #, k]&/@ptns[n-k, r], {r, 0, k}]]; a[n_] := Module[{i, l, v}, v=Infinity; For[i=n, True, i++, l=(Times@@Prime/@#&)/@ptns[i, n]; If[Min@@l>v, Return[v]]; minp=Min@@Select[l+1, ProvablePrimeQ]; If[minp<v, v=minp]]] (* First do <<NumberTheory`PrimeQ`. ptns[n, k] is list of partitions of n into exactly k parts *)
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CROSSREFS
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Sequence in context: A163268 A108562 A087523 this_sequence A162573 A087356 A042261
Adjacent sequences: A073916 A073917 A073918 this_sequence A073920 A073921 A073922
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 18 2002
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EXTENSIONS
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Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Nov 12 2002
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