A364719 Numbers k such that d(k) > d(k+1) > d(k+2) > d(k+3), where d(n) is the number of divisors of n.

80, 224, 260, 440, 464, 476, 560, 594, 650, 714, 836, 860, 884, 980, 1016, 1088, 1184, 1280, 1376, 1520, 1700, 1862, 1904, 2024, 2060, 2096, 2444, 2450, 2816, 2870, 2960, 2996, 3020, 3024, 3164, 3200, 3320, 3380, 3450, 3620, 3800, 3944, 3968, 4004, 4130, 4136, 4250

Offset: 1

Author

Seiichi Manyama, Aug 04 2023

Keywords

• nonn
• easy

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A050944, A075029.

Cf. A074827, A364718, A364720.

Programs

Mathematica

Flatten@Position[Differences@#&/@Partition[DivisorSigma[0,Range@5000],4,1], {?(#<0&)..}] (* _Hans Rudolf Widmer, Mar 11 2024 *)

PARI

isok(n) = numdiv(n)>numdiv(n+1) && numdiv(n+1)>numdiv(n+2) && numdiv(n+2)>numdiv(n+3);