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

1,1

Links

Table of n, a(n) for n=1..74.

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 *)

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).

Sequence in context: A180366 A340656 A346041 * A323644 A164702 A001745

Adjacent sequences: A341611 A341612 A341613 * A341615 A341616 A341617

Keyword

nonn

Author

Antti Karttunen, Feb 22 2021

Status

approved