A380931 Numbers k such that A380845(k) > 4*k.

5155920, 7733880, 10311840, 15467760, 20623680, 30935520, 41247360, 46403280, 61871040, 61901280, 75546240, 82494720, 87693480, 92806560, 103168800, 103194000, 113513400, 123742080, 123802560, 134152200, 140540400, 151092480, 151351200, 162162000, 164989440, 175386960

Offset

1,1

Comments

Analogous to 4-abundant numbers (A068404) with A380845 instead of A000203.

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Example

5155920 is a term since A380845(5155920) = 21067042 > 4 * 5155920 = 20623680.

Mathematica

q[k_] := Module[{h = DigitCount[k, 2, 1]}, DivisorSum[k, # &, DigitCount[#, 2, 1] == h &] > 4*k]; Select[Range[10^8], q]

Prog

(PARI) isok(k) = {my(h = hammingweight(k)); sumdiv(k, d, d*(hammingweight(d) == h)) > 4*k; }

Crossrefs

Cf. A000203, A380845, A380846, A380847, A380848.

Subsequence of A068404, A380929 and A380931.

Similar sequences: A307114, A340110.

Sequence in context: A157844 A263039 A241607 * A140658 A172715 A257153

Adjacent sequences: A380921 A380929 A380930 * A380932 A380933 A380938

Keyword

nonn,base,new

Author

Amiram Eldar, Feb 08 2025

Status

approved