A341614 Numbers k such that sigma(k) <= 2k < A003961(k).

4, 6, 8, 9, 10, 14, 15, 16, 21, 27, 28, 32, 35, 39, 44, 45, 49, 50, 52, 57, 63, 64, 68, 69, 75, 76, 81, 91, 92, 98, 99, 105, 110, 116, 117, 124, 125, 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, 242, 243, 244, 245, 248, 250, 255, 256

Offset: 1

Author

Antti Karttunen, Feb 22 2021

Keywords

• nonn

Crossrefs

Intersection of A263837 and A246282 (nonabundant numbers in A246282).

Union of A000396 and A341615.

Apparently also union of A337372 and A341611 (see also A341610).

Cf. A341612 (characteristic function), A326134 (a subsequence).

Programs

Mathematica

Select[Range[256], DivisorSigma[1, #] <= 2 # <
Times @@ Map[#1^#2 & @@ # &, FactorInteger[#] /. {p_, e_} /; e > 0 :> {Prime[PrimePi@ p + 1], e}] &] (* Michael De Vlieger, Feb 22 2021 *)