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A045920
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Numbers m such that the factorizations of m..m+1 have the same number of primes (including multiplicities).
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38
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2, 9, 14, 21, 25, 27, 33, 34, 38, 44, 57, 75, 85, 86, 93, 94, 98, 116, 118, 121, 122, 124, 133, 135, 141, 142, 145, 147, 153, 158, 164, 170, 171, 174, 177, 201, 202, 205, 213, 214, 217, 218, 230, 244, 245, 253, 284, 285, 296, 298, 301, 302, 326, 332, 334, 350, 356, 361
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OFFSET
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1,1
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COMMENTS
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This sequence is infinite (Heath-Brown, 1984). - Amiram Eldar, Jul 11 2020
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REFERENCES
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C. Clawson, Mathematical mysteries, Plenum Press 1996, p. 250.
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LINKS
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FORMULA
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MATHEMATICA
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Transpose[Transpose[Select[Partition[Table[{n, PrimeOmega[n]}, {n, 400}], 2, 1], #[[1, 2]]==#[[2, 2]]&]][[1]]][[1]] (* Harvey P. Dale, Feb 21 2012 *)
Position[Differences[PrimeOmega[Range[400]]], 0] // Flatten (* Zak Seidov, Oct 30 2012 *)
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PROG
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(Haskell)
import Data.List (elemIndices)
a045920 n = a045920_list !! (n-1)
a045920_list = map (+ 1) $ elemIndices 0 a076191_list
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CROSSREFS
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KEYWORD
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nice,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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