A364717 Numbers k such that d(k) < d(k+1) < d(k+2) < d(k+3) < d(k+4), where d(n) is the number of divisors of n.

11371, 11372, 35521, 38281, 45613, 48121, 50821, 50822, 52321, 52322, 54421, 54422, 59341, 59342, 71821, 79621, 86873, 87181, 117841, 125737, 127852, 130021, 130022, 132051, 132206, 133396, 151082, 153221, 173221, 180001, 184973, 186481, 195541, 195542, 196171, 196172

Offset

1,1

Links

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

Mathematica

d[k_] := d[k] = DivisorSigma[0, k]; Select[Range[200000], d[#] < d[#+1] < d[#+2] < d[#+3] < d[#+4] &] (* Amiram Eldar, Mar 11 2026 *)

Prog

(PARI) isok(n) = numdiv(n)<numdiv(n+1) && numdiv(n+1)<numdiv(n+2) && numdiv(n+2)<numdiv(n+3) && numdiv(n+3)<numdiv(n+4);

Crossrefs

Cf. A000005, A075028, A364720.

Cf. A074775, A364715, A364716.

Sequence in context: A067779 A202377 A210122 * A251957 A272552 A237796

Adjacent sequences: A364714 A364715 A364716 * A364718 A364719 A364720

Keyword

nonn

Author

Seiichi Manyama, Aug 04 2023

Status

approved