A380930 Numbers k such that A380845(k) > 3*k.

1080, 2160, 3600, 4320, 7200, 7440, 8640, 11340, 13608, 14400, 14880, 15120, 17280, 18600, 22680, 22860, 27216, 28800, 29760, 30240, 30480, 31752, 33264, 34020, 34560, 37200, 41664, 45360, 45720, 45900, 51408, 53340, 54432, 57600, 59520, 60480, 60960, 61200, 63504

Offset

1,1

Comments

Analogous to 3-abundant numbers (A068403) with A380845 instead of A000203.

Links

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

Formula

1080 is a term since A380845(1080) = 3330 > 3 * 1080 = 3240.

Mathematica

q[k_] := Module[{h = DigitCount[k, 2, 1]}, DivisorSum[k, # &, DigitCount[#, 2, 1] == h &] > 3*k]; Select[Range[64000], q]

Prog

(PARI) isok(k) = {my(h = hammingweight(k)); sumdiv(k, d, d*(hammingweight(d) == h)) > 3*k; }

Crossrefs

Cf. A000203, A380845, A380846, A380847.

Subsequence of A068403 and A380929.

Subsequences: A380848, A380931.

Similar sequences: A285615, A293187, A300664, A328135, A340109.

Sequence in context: A163562 A214621 A179688 * A159210 A250538 A281259

Adjacent sequences: A380927 A380928 A380929 * A380931 A380932 A380933

Keyword

nonn,base,easy

Author

Amiram Eldar, Feb 08 2025

Status

approved