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%I #7 Jun 25 2013 13:44:55
%S 0,0,0,0,0,1,1,2,3,4,5,6,8,11,15,22,26,32,44,56,74,100,126,163,220,
%T 284,376,486,627,817,1077,1392,1829,2354,3108,4020,5271,6861,8949,
%U 11625,15209,19790,25821,33671,43875,57165,74629,97186,126692,165238
%N Number of 3's in n-th term of A007651.
%H Peter J. C. Moses, <a href="/A022468/b022468.txt">Table of n, a(n) for n = 1..1000</a>
%t p={10,-15,11,-18,12,14,-25,12,-28,43,-13,2,0,-21,10,10,3,8,-10,-11,5,9,-18,16,-31,35,-20,15,-6,-10,36,-44,9,-1,3,16,-11,23,-3,-25,-17,-27,43,24,24,-33,-24,-7,14,6,9,-5,10,0,-9,-9,-12,7,14,7,-1,-9,-6,2,3,2,1,-1,0,-1,-1,0,0,1,0,0,0,0,0}; q={6,-9,9,-18,16,-11,14,-8,1,-5,7,2,8,-14,-5,-5,19,3,-6,-7,-6,16,-7,8,-22,17,-12,7,5,7,-8,4,-7,-9,13,-4,-6,14,-14,19,-7,-13,2,-4,18,0,-1,-4,-12,8,-5,0,8,1,7,-8,-5,-2,3,3,0,0,0,0,-2,-1,0,3,1,-1,-1,-1,1}; gf=Fold[x #1+#2&,0,p]/Fold[x #1+#2&,0,q]; CoefficientList[Series[gf,{x,0,99}],x] (* _Peter J. C. Moses_, Jun 24 2013 *)
%K nonn
%O 1,8
%A _Clark Kimberling_
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