A380929 Numbers k such that A380845(k) > 2*k.

36, 72, 84, 140, 144, 168, 180, 264, 270, 280, 288, 300, 336, 360, 372, 392, 450, 520, 528, 532, 540, 558, 560, 576, 594, 600, 612, 620, 672, 720, 744, 756, 780, 784, 840, 900, 930, 1036, 1040, 1050, 1056, 1064, 1068, 1080, 1092, 1116, 1120, 1134, 1152, 1170, 1180, 1188, 1200

Offset

1,1

Comments

Analogous to abundant numbers (A005101) with A380845 instead of A000203.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

36 is a term since A380845(36) = 84 > 2 * 36 = 72.

Mathematica

q[k_] := Module[{h = DigitCount[k, 2, 1]}, DivisorSum[k, # &, DigitCount[#, 2, 1] == h &] > 2*k]; Select[Range[1200], q]

Prog

(PARI) isok(k) = {my(h = hammingweight(k)); sumdiv(k, d, d*(hammingweight(d) == h)) > 2*k; }

Crossrefs

Cf. A000203, A380845, A380846.

Subsequence of A005101.

Subsequences: A380847, A380848, A380930, A380931.

Similar sequences: A034683, A064597, A087248, A129575, A129656, A292982, A348274, A348604, A379029.

Sequence in context: A260919 A247381 A249726 * A335463 A192026 A036785

Adjacent sequences: A380918 A380919 A380921 * A380930 A380931 A380932

Keyword

nonn,base,easy,new

Author

Amiram Eldar, Feb 08 2025

Status

approved