Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #17 Oct 19 2018 16:59:24
%S 3,28,282,2827,28274,282743,2827433,28274333,282743338,2827433388,
%T 28274333882,282743338823,2827433388230,28274333882308,
%U 282743338823081,2827433388230813,28274333882308139,282743338823081391,2827433388230813914
%N Floor of first differences of Pi*10^n.
%C For n>0, a(n) = decimal expansion of 9*Pi truncated to n-1 places.
%C This sequence is not the same as the first differences of A011545: 3, 28, 283, 2827, 28274, 282744, 2827433, 28274334, 282743339, 2827433388, ...
%F a(0)=3, a(n)=floor(Pi*10^n-Pi*10^(n-1)) for n>0.
%e a(2)=floor(Pi*10^2-Pi*10^1) = 282.
%t Join[{3},Differences[Pi*10^Range[0,20]]//Floor] (* _Harvey P. Dale_, Oct 19 2018 *)
%o (PARI) a(n) = if (n==0, 3, floor(Pi*10^n-Pi*10^(n-1))); \\ _Michel Marcus_, Mar 18 2014
%Y Cf. A011545.
%K nonn
%O 0,1
%A _Jeremy Gardiner_, Mar 14 2014