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A004778 Where records occur in A038548. 4

%I

%S 1,4,12,24,36,60,120,180,240,360,720,840,1260,1680,2520,5040,7560,

%T 10080,15120,20160,25200,27720,45360,50400,55440,83160,110880,166320,

%U 221760,277200,332640,498960,554400,665280,720720,1081080,1441440,2162160

%N Where records occur in A038548.

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

%C 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

%H Amiram Eldar, <a href="/A004778/b004778.txt">Table of n, a(n) for n = 1..436</a>

%H Amiram Eldar, <a href="/A004778/a004778.txt">Table of n, a(n), A038548(a(n)) for n = 1..436</a>

%t 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 *)

%o (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

%Y Cf. A038548, A038549, A086921, A086921.

%K easy,nonn

%O 1,2

%A _Chittaranjan Pardeshi_, Sep 19 2003

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Last modified August 13 05:41 EDT 2020. Contains 336442 sequences. (Running on oeis4.)