A364720 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.

28974, 28975, 39150, 39444, 39445, 44863, 60775, 64015, 68875, 71995, 75174, 79135, 79848, 79849, 91195, 103615, 113904, 113905, 118825, 126294, 141955, 143143, 148974, 149823, 150955, 154375, 160734, 160735, 160974, 161343, 167824, 171925, 177330, 181194, 181195

Offset: 1

Author

Seiichi Manyama, Aug 04 2023

Keywords

• nonn
• easy

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000005, A075029.

Cf. A074827, A364718, A364719.

Programs

Mathematica

Flatten@Position[Differences@# &/@Partition[DivisorSigma[0, Range@1000000],5,1], {?(# < 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) && numdiv(n+3)>numdiv(n+4);