A341611 Nonabundant numbers that are not primitive terms of A246282.

8, 16, 27, 28, 32, 44, 45, 50, 52, 63, 64, 68, 75, 76, 81, 92, 98, 99, 105, 110, 116, 117, 124, 128, 130, 135, 136, 147, 148, 152, 153, 154, 164, 165, 170, 171, 172, 175, 182, 184, 188, 189, 190, 195, 207, 212, 225, 230, 231, 232, 236, 238, 243, 244, 245, 248, 250, 255, 256, 261, 266, 268, 273, 279, 284, 285, 290, 292, 296, 297

Offset: 1

Author

Antti Karttunen, Feb 22 2021

Keywords

• nonn

Comments

Terms k of A263837 for which A337345(k) > 1 (or equally, for which A337346(k) > 0).

Numbers k such that sigma(k) <= 2k and k has at least two distinct divisors d such that 2d < A003961(d). By necessity, one of these divisors is then k itself.

Crossrefs

Intersection of A341610 and A263837. Subsequence of A341614.

Cf. A000203, A003961, A337345, A337346.

Programs

PARI

A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A337345(n) = sumdiv(n,d,A003961(d)>(d+d));
isA341611(n) = ((sigma(n)<=(2*n))&&(1<A337345(n)));