cp's OEIS Frontend

A122145 Numbers k such that q(k) < M(k) where q(k) is the largest prime divisor of k and M(k) is the largest prime power divisor of k.

%I A122145 #13 May 23 2024 04:31:57
%S A122145 4,8,9,12,16,18,24,25,27,32,36,40,45,48,49,50,54,56,63,64,72,75,80,81,
%T A122145 90,96,98,100,108,112,120,121,125,126,128,135,144,147,150,160,162,168,
%U A122145 169,175,176,180,189,192,196,200,208,216,224,225,240,242,243,245,250
%N A122145 Numbers k such that q(k) < M(k) where q(k) is the largest prime divisor of k and M(k) is the largest prime power divisor of k.
%H A122145 Charles R Greathouse IV, <a href="/A122145/b122145.txt">Table of n, a(n) for n = 1..10000</a>
%t A122145 Select[Range[250], Max[Power @@@ (f = FactorInteger[#])] > f[[-1, 1]] &] (* _Amiram Eldar_, May 23 2024 *)
%o A122145 (PARI) is(n)=my(f=factor(n),k=#f[,1]);for(i=1,k, if(f[i,1]^f[i,2]>f[k,1], return(1)));0 \\ _Charles R Greathouse IV_, Sep 20 2012
%Y A122145 Cf. A006530, A034699, A122144, A122146.
%K A122145 nonn
%O A122145 1,1
%A A122145 Douglas Stones (dssto1(AT)student.monash.edu.au), Aug 22 2006
%E A122145 Extended by _Ray Chandler_, Aug 23 2006