Search: id:A069781
Results 1-1 of 1 results found.

%I A069781
%S A069781 432,576,648,1600,2000,2160,2880,2916,3024,3136,3240,4032,4536,4752,
%T A069781 4800,5000,5488,5616,6000,6336,7128,7344,7488,7744,8208,8424,9408,9792,
%U A069781 9936,10125,10800,10816,10944,11016,11200,12312,12528,13248,13392
%N A069781 n is such that GCD[d(n^3),d(n)] is not a power of 2.
%F A069781 Log [2, GCD[A000005(n^3), A000005(n)]] is nonintegral.
%e A069781 For n<100000,GCD[d(n^3),d[n]]={5,7,10,14,20,28,40,80} which is obtained 
               for n={20736,576,432,2880,54000,20160,2160,15120} respectively.
%t A069781 f[x_] := GCD[DivisorSigma[0, x^3], DivisorSigma[0, x]] Do[s=f[n]; If[ 
               !IntegerQ[Log[2, s]], Print[n]], {n, 1, 100000}]
%Y A069781 Cf. A000005, A061701, A037992, A069780, A069782.
%Y A069781 Sequence in context: A063463 A175026 A066419 this_sequence A006910 A015229 
               A109123
%Y A069781 Adjacent sequences: A069778 A069779 A069780 this_sequence A069782 A069783 
               A069784
%K A069781 easy,nonn
%O A069781 1,1
%A A069781 Labos E. (labos(AT)ana.sote.hu), Apr 08 2002

Search completed in 0.001 seconds