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 A212166 Numbers n such that the maximal exponent in its prime factorization equals the number of positive exponents (A051903(n) = A001221(n)). 9
 1, 2, 3, 5, 7, 11, 12, 13, 17, 18, 19, 20, 23, 28, 29, 31, 36, 37, 41, 43, 44, 45, 47, 50, 52, 53, 59, 61, 63, 67, 68, 71, 73, 75, 76, 79, 83, 89, 92, 97, 98, 99, 100, 101, 103, 107, 109, 113, 116, 117, 120, 124, 127, 131, 137, 139, 147, 148, 149, 151, 153 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A225230(a(n)) = 0; A050326(a(n)) = 1. - Reinhard Zumkeller, May 03 2013 REFERENCES M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 844. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. Primefan, The First 2500 Integers Factored (first of 5 pages) EXAMPLE 36 = 2^2*3^2 has 2 positive exponents in its prime factorization. The maximal exponent in its prime factorization is also 2. Therefore, 36 belongs to this sequence. MATHEMATICA okQ[n_] := Module[{f = Transpose[FactorInteger[n]][[2]]}, Max[f] == Length[f]]; Select[Range[424], okQ] (* T. D. Noe, May 24 2012 *) PROG (Haskell) import Data.List (elemIndices) a212166 n = a212166_list !! (n-1) a212166_list = map (+ 1) \$ elemIndices 0 a225230_list -- Reinhard Zumkeller, May 03 2013 CROSSREFS Includes subsequences A000040, A006939, A138534, A181555, A181825. See also A212164-A212165, A212167-A212168. Cf. A188654 (complement). Sequence in context: A119251 A182358 A336418 * A293511 A336615 A325337 Adjacent sequences: A212163 A212164 A212165 * A212167 A212168 A212169 KEYWORD nonn AUTHOR Matthew Vandermast, May 22 2012 STATUS approved

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Last modified December 8 13:46 EST 2023. Contains 367679 sequences. (Running on oeis4.)