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%I #16 Jan 22 2019 20:40:01
%S 16,48,81,320,351,486,512,625,1080,1260,1350,1375,1792,1836,2070,2145,
%T 2175,2401,2730,2772,3072,3150,3510,4104,4305,4625,4650,4655,4998,
%U 5880,6000,6174,6545,7098,7128,7182,7650,7791,7889,7956,9030,9108,9295,9324
%N Composite numbers such that the square root of the sum of squares of their prime factors (with multiplicity) is an integer.
%H Hieronymus Fischer, <a href="/A134605/b134605.txt">Table of n, a(n) for n = 1..10000</a>
%e a(2)=48 since 48=2*2*2*2*3 and sqrt(4*2^2+3^2)=sqrt(25)=5.
%t srssQ[n_]:=IntegerQ[Sqrt[Total[Flatten[Table[#[[1]],#[[2]]]&/@ FactorInteger[ n]]^2]]]; Select[Range[10000],CompositeQ[#]&&srssQ[#]&] (* _Harvey P. Dale_, Jan 22 2019 *)
%o (PARI) is(n)=my(f=factor(n)); issquare(sum(i=1,#f~,f[i,1]^2*f[i,2])) && !isprime(n) && n>1 \\ _Charles R Greathouse IV_, Apr 29 2015
%Y Cf. A001597, A025475, A134333, A134344, A134376, A134600, A134602, A134608, A134611, A134616, A134618, A134620.
%K nonn
%O 1,1
%A _Hieronymus Fischer_, Nov 11 2007
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