cp's OEIS Frontend

A107924 Even numbers n such that n^2 is an arithmetic number.

%I A107924 #13 Aug 06 2014 09:33:54
%S A107924 296,536,632,872,1208,1304,1544,2072,2216,2648,2984,3584,3656,3752,
%T A107924 3848,3896,3904,3992,4328,4424,4568,4904,5624,5672,5912,6008,6104,
%U A107924 6584,6968,7016,7256,7352,7928,8216,8264,8456,8696,8896,8936,9032,9128,9176,9368
%N A107924 Even numbers n such that n^2 is an arithmetic number.
%C A107924 Odd numbers with this property are much more numerous, cf. A107925, A003601 (arithmetic number).
%H A107924 R. J. Mathar, Michael De Vlieger, <a href="/A107924/b107924.txt">Table of n, a(n) for n = 1..10778</a> (first 443 terms from R. J. Mathar)
%p A107924 isA107924 := proc(n)
%p A107924     if type(n,'even') then
%p A107924         dvs := numtheory[divisors](n^2) ;
%p A107924         add(d,d=dvs)/nops(dvs) ;
%p A107924         if type(%,'integer') then
%p A107924             true;
%p A107924         else
%p A107924             false;
%p A107924         end if;
%p A107924     else
%p A107924         false;
%p A107924     end if;
%p A107924 end proc:
%p A107924 n := 1 :
%p A107924 for k from 2 to 100000 do
%p A107924     if isA107924(k) then
%p A107924         printf("%d %d\n",n,k) ;
%p A107924         n := n+1 ;
%p A107924     end if;
%p A107924 end do: # create b-file, _R. J. Mathar_, Jul 28 2014
%t A107924 Select[Range[2, 10000, 2], Mod[DivisorSigma[1, #^2], DivisorSigma[0, #^2]]==0&]
%Y A107924 Cf. A003601, A107925.
%K A107924 nonn,easy
%O A107924 1,1
%A A107924 _Zak Seidov_, Jun 10 2005