A204829 Numbers with abundancy 2 <= a < 3.

6, 12, 18, 20, 24, 28, 30, 36, 40, 42, 48, 54, 56, 60, 66, 70, 72, 78, 80, 84, 88, 90, 96, 100, 102, 104, 108, 112, 114, 126, 132, 138, 140, 144, 150, 156, 160, 162, 168, 174, 176, 186, 192, 196, 198, 200, 204, 208, 210, 216, 220, 222, 224, 228, 234, 246, 252

Offset

1,1

Comments

Numbers m such that 2 <= sigma(m) / m < 3.

Supersequence of A000396 (perfect numbers).

Links

Jaroslav Krizek and T. D. Noe, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Abundancy

Eric Weisstein's World of Mathematics, Abundant Number

Example

Number 70 is in sequence because sigma(70) / 70 = 144 / 70, which is between 2 and 3.

Crossrefs

Cf. A204828 (abundant numbers with abundancy 3 <= a < 4).

Sequence in context: A326133 A177052 A023196 * A005835 A007620 A100715

Adjacent sequences: A204826 A204827 A204828 * A204830 A204831 A204832

Keyword

nonn

Author

Jaroslav Krizek, Jan 22 2012

Status

approved