%I A087405
%S A087405 2,2,22,98,502,2498,12502,62498,312502,1562498,7812502,39062498,
%T A087405 195312502,976562498,4882812502,24414062498,122070312502,610351562498,
%U A087405 3051757812502,15258789062498,76293945312502,381469726562498
%N A087405 First differences of A087404: a(n)=A087404(n)-A087404(n-1), a(0)=A087404(0).
%F A087405 G.f.: ((1-x)(2-4x))/(1-4x-5x^2). For n>0: a(n)=4*5^(n-1)+2(-1)^n
%t A087405 CoefficientList[Series[((1 - x)(2 - 4x))/(1 - 4x - 5x^2), {x, 0, 25}], 
               x]
%Y A087405 Sequence in context: A143807 A118454 A118326 this_sequence A001012 A040082 
               A014358
%Y A087405 Adjacent sequences: A087402 A087403 A087404 this_sequence A087406 A087407 
               A087408
%K A087405 easy,nonn
%O A087405 0,1
%A A087405 Mario Catalani (mario.catalani(AT)unito.it), Sep 01 2003