%I #21 Jan 05 2024 11:02:36
%S 1,4,8,16,32,36,64,72,128,144,216,256,288,432,512,576,864,900,1024,
%T 1152,1296,1728,1800,2048,2304,2592,3456,3600,4096,4608,5184,5400,
%U 6912,7200,7776,8192,9216,10368,10800,13824,14400,15552,16384,18432,20736,21600,27000
%N Powerful numbers that are the least integer of their prime signature.
%C Apart from 1, all terms in this sequence are multiples of 4. - _Charles R Greathouse IV_, Dec 13 2016
%H Amiram Eldar, <a href="/A181800/b181800.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Charles R Greathouse IV)
%F Intersection of A001694 and A025487.
%o (PARI) is(n)=if(n<4,return(n==1)); my(f=factor(n)); vecmin(f[,2])>1 && f[,1]~ == primes(#f~) && f[,2] == vecsort(f[,2],,4) \\ _Charles R Greathouse IV_, Sep 14 2015
%Y Cf. A001694 (powerful numbers), A025487 (least integer of each prime signature).
%K nonn
%O 1,2
%A _Matthew Vandermast_, Dec 02 2010