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A162966 Union of 1 and nonsquarefree numbers (A013929). 0
1, 4, 8, 9, 12, 16, 18, 20, 24, 25, 27, 28, 32, 36, 40, 44, 45, 48, 49, 50, 52, 54, 56, 60, 63, 64, 68, 72, 75, 76, 80, 81, 84, 88, 90, 92, 96, 98, 99, 100, 104, 108, 112, 116, 117, 120, 121, 124, 125, 126, 128, 132, 135, 136, 140, 144, 147, 148, 150, 152, 153, 156, 160 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Or, the natural numbers that are not products of distinct primes. Also, number of prime divisors of n < number of nonprime divisors of n. - Juri-Stepan Gerasimov, Nov 10 2009

LINKS

Table of n, a(n) for n=1..63.

MATHEMATICA

t = {1}; Do[If[Max[Transpose[FactorInteger[n]][[2]]] > 1, AppendTo[t, n]], {n, 2, 160}]; t (* Jayanta Basu, Apr 30 2013 *)

PROG

(PARI) is(n)=!issquarefree(n)||n==1 \\ Charles R Greathouse IV, Apr 04 2014

CROSSREFS

Cf. A013929.

Sequence in context: A259241 A289553 A013929 * A190641 A327877 A034043

Adjacent sequences:  A162963 A162964 A162965 * A162967 A162968 A162969

KEYWORD

nonn,less

AUTHOR

Jaroslav Krizek, Jul 19 2009

STATUS

approved

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Last modified September 30 23:44 EDT 2020. Contains 337440 sequences. (Running on oeis4.)