A326133 Numbers n for which sigma(n) > A005187(n).

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, 110, 112, 114, 120, 126, 132, 138, 140, 144, 150, 156, 160, 162, 168, 174, 176, 180, 186, 192, 196, 198, 200, 204, 208, 210, 216, 220, 222, 224, 228, 234, 240, 246, 252, 258, 260, 264, 270, 272, 276, 280, 282, 288, 294, 300

Offset

1,1

Comments

Differs from A023196 for the first time at the 28th term, which here is 110, which is not included in A023196.

Note that as there is at least one odd number (815634435) in A326138, it means that A005231 does not contain all odd terms of this sequence.

Links

Antti Karttunen, Table of n, a(n) for n = 1..16260

Index entries for sequences related to binary expansion of n.

Index entries for sequences related to sigma(n).

Index entries for sequences where any odd perfect numbers must occur.

Mathematica

Select[Range[300], DivisorSigma[1, #] > 2*# - DigitCount[2*#, 2, 1] &] (* Amiram Eldar, Aug 06 2023 *)

Prog

(PARI)
A005187(n) = { my(s=n); while(n>>=1, s+=n); s; };
isA326133(n) = (sigma(n)>A005187(n));

Crossrefs

Positions of negative terms in A294898.

Cf. A000203, A005187, A023196.

Cf. A000396, A005231, A083207, A111592, A326131, A326138 (subsequences).

Sequence in context: A119357 A097216 A346695 * A177052 A023196 A204829

Adjacent sequences: A326130 A326131 A326132 * A326134 A326135 A326136

Keyword

nonn

Author

Antti Karttunen, Jun 11 2019

Status

approved