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A341614
Numbers k such that sigma(k) <= 2k < A003961(k).
8
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
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: A340656 A373482 A346041 * A323644 A164702 A001745
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 22 2021
STATUS
approved