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A085155 Powers of semiprimes. 7

%I #19 Mar 04 2017 10:11:42

%S 1,4,6,9,10,14,15,16,21,22,25,26,33,34,35,36,38,39,46,49,51,55,57,58,

%T 62,64,65,69,74,77,81,82,85,86,87,91,93,94,95,100,106,111,115,118,119,

%U 121,122,123,129,133,134,141,142,143,145,146,155,158,159,161,166

%N Powers of semiprimes.

%C Numbers of form A001358(i)^j;

%C m>1 is a term iff A067029(m)=A071178(m) and (A001221(m)=2 or A067029(m) is even).

%H Reinhard Zumkeller, <a href="/A085155/b085155.txt">Table of n, a(n) for n = 1..10000</a>

%F {1} UNION {A001358 semiprimes} UNION {A074985 squares of semiprimes} UNION {cubes of semiprimes} UNION {4th powers of semiprimes} UNION ... - _Jonathan Vos Post_, Sep 06 2006

%t Select[Range@ 166, Function[n, Or[n == 1, And[Length@ # == 1, EvenQ@ First@ #], And[Length@ # == 2, SameQ @@ #]] &[FactorInteger[n][[All, -1]]]]] (* _Michael De Vlieger_, Mar 04 2017 *)

%o (PARI) is(n)=my(f=factor(n)[,2]); #f==0 || (#f==2 && f[1]==f[2]) || (#f==1 && f[1]%2==0) \\ _Charles R Greathouse IV_, Oct 19 2015

%Y Semiprime analog of A000961 = prime powers.

%Y Cf. A001358, A074985, A085156.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Jun 21 2003

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