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

1,1

Comments

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

Links

Table of n, a(n) for n=1..45.

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

Prog

(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)));

Crossrefs

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

Sequence in context: A223156 A087702 A224565 * A295768 A255917 A154071

Adjacent sequences: A341601 A341602 A341603 * A341605 A341606 A341607

Keyword

nonn

Author

Antti Karttunen, Feb 20 2021

Status

approved