%I #16 Dec 31 2022 11:28:31
%S 10,90,900,9000,90000,900000,9000000,90000000,900000000,9000000000,
%T 90000000000,900000000000,9000000000000,90000000000000,
%U 900000000000000,9000000000000000,90000000000000000,900000000000000000,9000000000000000000,90000000000000000000
%N Number of nonnegative integers with n digits.
%C Also, first differences of A000533. - _Omar E. Pol_, Feb 24 2011
%F a(1) = 10, a(2) = 90, a(n) = a(n-1)*10 for n>2.
%F a(n) = A052268(n), n>1. - _R. J. Mathar_, Oct 02 2008
%p a:= n-> `if`(n=1, 10, 9*10^(n-1)):
%p seq(a(n), n=1..30); # _Alois P. Heinz_, Sep 12 2012
%t Join[{10},NestList[10#&,90,20]] (* _Harvey P. Dale_, Dec 31 2022 *)
%Y Column k=1 of A216653.
%K base,easy,nonn
%O 1,1
%A _Shyam Sunder Gupta_, Sep 01 2001
|