%I #9 Mar 31 2012 10:32:40

%S 1,13,169,1890,20216,210824,2167819,22119495,224576508,2272476724,

%T 22940979719,231196075659,2326967290816,23397529216327,

%U 235077715264515,2360380831212204,23688221424314913,237630022857420415,2382971166402199310,23889590198849417292

%N Number of odd composites 1 mod 4 less than 10^n.

%F Count odd composites 1 mod 4 less than 10^n

%F For n>1, a(n) = 25*10^(n-2) - 1 - A091098(n). - _Max Alekseyev_, May 30 2007

%e Below 10^2 there are 13 odd composites so a(2)=13

%Y Cf. A093152 A093153 A091295 A091098 A091099.

%K nonn

%O 1,2

%A _Enoch Haga_, Mar 24 2004

%E More terms from _Max Alekseyev_, May 30 2007

%E Extended by _Max Alekseyev_, Oct 13 2009