Loading ...
Sorry, an error occurred while loading the content.

A073694

Expand Messages
  • djbroadhurst
    ... Why stop at such small values? It takes little time to go up to n=10^5. By brute force: {A(n)=local(o);o=n;while(o%2==0,o=o/2);
    Message 1 of 1 , Sep 2, 2002
    • 0 Attachment
      "Max B" wrote:

      > A073694
      > Sequence: 5,32,50,162,512,1984,2450
      > Name: n such that the number of divisors of n
      > = number of anti-divisors of n.

      Why stop at such small values?
      It takes little time to go up to n=10^5.
      By brute force:

      {A(n)=local(o);o=n;while(o%2==0,o=o/2);
      sigma(2*n+1,0)+sigma(2*n-1,0)+sigma(o,0)-5}
      for(n=1,10^5,if(A(n)==sigma(n,0),print(n)))

      5
      32
      50
      162
      512
      1984
      2450
      3784
      5408
      7564
      9248
      15488
      19208
      22684
      26680
      30752
      53792
      79600
      85698
      Good bye!
    Your message has been successfully submitted and would be delivered to recipients shortly.