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

990, 1170, 4590, 7650, 8550, 19470, 23562, 23868, 26334, 27324, 27846, 31050, 31878, 34452, 35190, 39330, 40194, 44370, 47430, 49590, 53010, 56610, 60030, 62730, 63270, 64170, 65790, 70110, 71910, 73530, 76590, 80370, 80910, 81090, 84870, 90270, 90630, 93330, 93366, 100890, 102510, 104310, 108630, 111690, 117450

Offset: 1

Author

Antti Karttunen, Feb 20 2021

Keywords

• nonn

Comments

Terms k of A337479 for which A337690(k) = 1.

Links

• Index entries for sequences computed from indices in prime factorization
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A003961, A006039, A337386, A337479, A337539, A337690.

Programs

PARI

A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
isA337386(n) = { my(x=A003961(n)); (sigma(x)>=2*x); };
isA337479(n) = (isA337386(n)&&(1==sumdiv(n,d,isA337386(d))));
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
isA006039(n) = ((sigma(n)==(2*n))||isA071395(n));
A337690(n) = sumdiv(n,d,isA006039(d));
isA341604(n) = (isA337479(n)&&(1==A337690(n)));