A364718 - OEIS

A364718

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

45, 80, 81, 105, 165, 224, 225, 260, 261, 272, 315, 324, 345, 357, 384, 405, 435, 440, 441, 464, 465, 476, 477, 495, 512, 555, 560, 561, 567, 585, 594, 595, 620, 624, 627, 650, 651, 675, 704, 714, 715, 795, 800, 825, 836, 837, 855, 860, 861, 884, 885, 891, 896, 915

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

MATHEMATICA

d[k_] := d[k] = DivisorSigma[0, k]; Select[Range[1000], d[#] > d[#+1] > d[#+2] &] (* Amiram Eldar, Mar 11 2026 *)

PROG

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

CROSSREFS

Cf. A000005, A075029, A364657.

Cf. A074827, A364719, A364720.