A063072 Sum of divisors of Ramanujan's highly composite numbers, or sigma(A002182(n)).

1, 3, 7, 12, 28, 60, 91, 124, 168, 360, 546, 744, 1170, 2418, 2880, 4368, 5952, 9360, 19344, 28800, 39312, 59520, 79248, 99944, 112320, 180048, 203112, 232128, 345600, 471744, 714240, 950976, 1199328, 1451520, 2160576, 2437344, 2926080

Offset: 1

Author

Jason Earls, Aug 02 2001

Keywords

• easy
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..50 from Harry J. Smith)

Crossrefs

Cf. A000005, A004394, A002182, A002183, A002473, A000203.

Programs

Mathematica

s={}; dm=0; Do[d = DivisorSigma[0,n]; If[d > dm, dm=d; AppendTo[s, DivisorSigma[1,n]]], {n, 1, 10^5}]; s (* Amiram Eldar, Jun 28 2019 *)

PARI

a=0; j=[]; for(n=1,200000,b=numdiv(n); if(b>a,a=b; j=concat(j, sigma(n)))); j

PARI

{ n=a=0; for (m=1, 10^9, b=numdiv(m); if(b>a, a=b; write("b063072.txt", n++, " ", sigma(m)); if (n==50, break)) ) } \\ Harry J. Smith, Aug 16 2009

Formula

a(n) = A000203(A002182(n)). - Michel Marcus, Jun 28 2018

Extensions

More terms from Reiner Martin, Dec 22 2001