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 A122444 Greatest prime factor of powers of semiprimes. 2
 1, 2, 3, 3, 5, 7, 5, 2, 7, 11, 5, 13, 11, 17, 7, 3, 19, 13, 23, 7, 17, 11, 19, 29, 31, 2, 13, 23, 37, 11, 3, 41, 17, 43, 29, 13, 31, 47, 19, 5, 53, 37, 23, 59, 17, 11, 61, 41, 43, 19, 67, 47, 71, 13, 29, 73, 31, 79, 53, 23, 83 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A122443 is least prime factor of powers of semiprimes. Cf. A076397 Largest prime factor of n-th perfect power. LINKS Michael De Vlieger, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A006530(A085155(n)) = greatest prime factor of A085155 powers of semiprimes. MATHEMATICA FactorInteger[#][[-1, 1]] & /@ Select[Range@ 168, Function[n, Or[n == 1, And[Length@ # == 1, EvenQ@ First@ #], And[Length@ # == 2, SameQ @@ #]] &[FactorInteger[n][[All, -1]]]]] (* Michael De Vlieger, Mar 04 2017 *) CROSSREFS Cf. A000040, A001358, A006530, A020639, A076396, A076397, A085155, A122443. Sequence in context: A144680 A209702 A077558 * A373751 A066072 A239586 Adjacent sequences: A122441 A122442 A122443 * A122445 A122446 A122447 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Sep 06 2006 STATUS approved

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Last modified August 14 18:55 EDT 2024. Contains 375166 sequences. (Running on oeis4.)