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A060476
Let n = 2^e_2 * 3^e_3 * 5^e_5 * ... be the prime factorization of n; sequence gives n such that 1 + max{e_2, e_3, ...} is nonprime.
9
1, 8, 24, 27, 32, 40, 54, 56, 72, 88, 96, 104, 108, 120, 125, 128, 135, 136, 152, 160, 168, 184, 189, 200, 216, 224, 232, 243, 248, 250, 256, 264, 270, 280, 288, 296, 297, 312, 328, 343, 344, 351, 352, 360, 375, 376, 378, 384, 392, 408, 416, 424, 440, 456, 459, 472, 480
OFFSET
1,2
COMMENTS
The old entry with this sequence number was a duplicate of A005171.
The asymptotic density of this sequence is Sum_{c composite} (1/zeta(c) - 1/zeta(c-1)) = 0.1182437806... - Amiram Eldar, Oct 18 2020
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
From Reinhard Zumkeller, Nov 30 2015: (Start)
A010051(A051903(a(n)+1)) = 1.
a(A055229(n)) > 1 for n > 1. (End)
MATHEMATICA
Join[{1}, Select[Range[500], !PrimeQ[1+Max[FactorInteger[#][[All, 2]]]]&]] (* Jean-François Alcover, Aug 02 2018 *)
PROG
(PARI) isA060476(n) = if(n<2, 1, !isprime(vecmax(factor(n)[, 2])+1))
(Haskell)
a060476 n = a060476_list !! (n-1)
a060476_list = filter ((== 0) . a010051' . (+ 1) . a051903) [1..]
-- Reinhard Zumkeller, Nov 30 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 18 2008
STATUS
approved