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A076690
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Nearest integer to average of the smallest and largest prime factors of n (0.5 is rounded to 1).
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1
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2, 3, 2, 5, 3, 7, 2, 3, 4, 11, 3, 13, 5, 4, 2, 17, 3, 19, 4, 5, 7, 23, 3, 5, 8, 3, 5, 29, 4, 31, 2, 7, 10, 6, 3, 37, 11, 8, 4, 41, 5, 43, 7, 4, 13, 47, 3, 7, 4, 10, 8, 53, 3, 8, 5, 11, 16, 59, 4, 61, 17, 5, 2, 9, 7, 67, 10, 13, 5, 71, 3, 73, 20, 4, 11, 9, 8, 79, 4, 3, 22, 83, 5, 11, 23, 16
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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EXAMPLE
| The smallest and largest prime factors of 6 are 2 and 3, respectively, the average of which is 2.5, rounding off to 3. Hence a(6) = 3.
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MATHEMATICA
| f[n_] := Module[{p, l}, p = Transpose[FactorInteger[n]][[1]]; l = Length[p]; Ceiling[(p[[1]] + p[[l]])/2]]; Table[f[i], {i, 2, 100}]
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CROSSREFS
| Sequence in context: A109674 A067629 A079870 * A086287 A090662 A088387
Adjacent sequences: A076687 A076688 A076689 * A076691 A076692 A076693
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KEYWORD
| easy,nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 25 2002
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