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

1,1

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.

Links

Table of n, a(n) for n=1..70.

Prog

(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)));

Crossrefs

Intersection of A341610 and A263837. Subsequence of A341614.

Cf. A000203, A003961, A337345, A337346.

Sequence in context: A302537 A074750 A190519 * A083419 A329134 A090081

Adjacent sequences: A341608 A341609 A341610 * A341612 A341613 A341614

Keyword

nonn

Author

Antti Karttunen, Feb 22 2021

Status

approved