|
%I #5 Nov 21 2013 12:50:02
%S 1,7,28,63,186,508,1016,2047,6643,12282,24564,65532,114674,262136,
%T 786408,1048575,2359278,6815731,10485740,25165818,67108832,100663284,
%U 201326568,536870908,1040187361,1879048178,5368709080,8589934584
%N a(n) = sigma(n*2^(n-1)).
%F Logarithmic derivative of A176361.
%t Table[DivisorSigma[1,n 2^(n-1)],{n,40}] (* _Harvey P. Dale_, Mar 11 2011 *)
%o (PARI) a(n)=sigma(n*2^(n-1))
%Y Cf. A176361, A176311, A000203 (sigma).
%K nonn
%O 1,2
%A _Paul D. Hanna_, Apr 15 2010
|
