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A341604 Those primitive elements of A337386 that have exactly one primitive nondeficient divisor (A006039).

%I A341604 #7 Feb 20 2021 23:11:42
%S A341604 990,1170,4590,7650,8550,19470,23562,23868,26334,27324,27846,31050,
%T A341604 31878,34452,35190,39330,40194,44370,47430,49590,53010,56610,60030,
%U A341604 62730,63270,64170,65790,70110,71910,73530,76590,80370,80910,81090,84870,90270,90630,93330,93366,100890,102510,104310,108630,111690,117450
%N A341604 Those primitive elements of A337386 that have exactly one primitive nondeficient divisor (A006039).
%C A341604 Terms k of A337479 for which A337690(k) = 1.
%H A341604 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H A341604 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%o A341604 (PARI)
%o A341604 A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
%o A341604 isA337386(n) = { my(x=A003961(n)); (sigma(x)>=2*x); };
%o A341604 isA337479(n) = (isA337386(n)&&(1==sumdiv(n,d,isA337386(d))));
%o A341604 isA071395(n) = if(sigma(n) <= 2*n, 0, fordiv(n, d, if((d != n)&&(sigma(d) >= 2*d), return(0))); (1)); \\ After code  in A071395
%o A341604 isA006039(n) = ((sigma(n)==(2*n))||isA071395(n));
%o A341604 A337690(n) = sumdiv(n,d,isA006039(d));
%o A341604 isA341604(n) = (isA337479(n)&&(1==A337690(n)));
%Y A341604 Cf. A003961, A006039, A337386, A337479, A337539, A337690.
%K A341604 nonn
%O A341604 1,1
%A A341604 _Antti Karttunen_, Feb 20 2021