A089889 - OEIS

%I #3 Mar 30 2012 18:50:42

%S 1,2,4,8,16,32,64,128,192,384,768,1536,3072,6144,12288,16384,32768,

%T 65536,131072,262144,524288,1048576,2097152,4194304,5242880,10485760,

%U 20971520,41943040,83886080,167772160,335544320,671088640,1342177280

%N Number of subsets of {1,.., n} containing exactly one square.

%C a(n)=A000196(n)*A089887(n);

%C for n>1: a(n) = A089886(n,1).

%F a(n) = n^(1/2) * 2^(n-n^(1/2)).

%Y Cf. A089890.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Nov 13 2003