A004778 Where records occur in A038548.

1, 4, 12, 24, 36, 60, 120, 180, 240, 360, 720, 840, 1260, 1680, 2520, 5040, 7560, 10080, 15120, 20160, 25200, 27720, 45360, 50400, 55440, 83160, 110880, 166320, 221760, 277200, 332640, 498960, 554400, 665280, 720720, 1081080, 1441440, 2162160

Offset: 1

Author

Chittaranjan Pardeshi, Sep 19 2003

Keywords

• easy
• nonn

Comments

Records are 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, ...

This sequence coincides with the highly composite numbers (A002182) excluding 2, 6, and 48. These excluded numbers occur directly after the only squares of A002182, namely 1, 4, and 36. - Jaycob Coleman, Mar 08 2015

Links

• Amiram Eldar, Table of n, a(n) for n = 1..436
• Amiram Eldar, Table of n, a(n), A038548(a(n)) for n = 1..436

Crossrefs

Cf. A038548, A038549, A086921, A086921.

Programs

Mathematica

s={}; dm = 0; Do[d =Ceiling[DivisorSigma[0,n]/2]; If[d > dm, dm = d; AppendTo[s, n]], {n, 10^5}]; s (* Amiram Eldar, Jul 07 2019 *)

PARI

lista(nn) = {rec = 0; for (n=1, nn, nb = ceil(numdiv(n)/2); if (nb > rec, print1(n, ", "); rec = nb;););} \\ Michel Marcus, Sep 01 2013