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

1,2

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

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 *)

Prog

(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

Crossrefs

Cf. A038548, A038549, A086921, A086921.

Sequence in context: A008122 A008103 A086921 * A038549 A008081 A301053

Adjacent sequences: A004775 A004776 A004777 * A004779 A004780 A004781

Keyword

easy,nonn

Author

Chittaranjan Pardeshi, Sep 19 2003

Status

approved