%I A098455
%S A098455 1,2,24,128,1096,7632,60864,461568,3648096,28551872,226695424,
%T A098455 1799989248,14380907776,115126211072,924791445504,7444100947968,
%U A098455 60057602459136,485388465196032,3929580292706304,31858982479331328
%N A098455 Expansion of 1/sqrt(1-4x-36x^2).
%C A098455 Define Q(n,x)=sum{k=0..floor(n/2), binomial(n,k)binomial(2(n-k),n)x^(n-2k)}. 
               Then a(n)=3^n*Q(n,1/3). A084770(n) is 2^n*Q(n,1/2). Central coefficient 
               of (1+2x+10x^2)^n.
%F A098455 E.g.f.: exp(2x)BesselI(0, 2sqrt(10)x); a(n)=sum{k=0..floor(n/2), binomial(n, 
               k)binomial(2(n-k), n)9^k}.
%Y A098455 Sequence in context: A034310 A060817 A045820 this_sequence A078994 A000185 
               A163752
%Y A098455 Adjacent sequences: A098452 A098453 A098454 this_sequence A098456 A098457 
               A098458
%K A098455 easy,nonn
%O A098455 0,2
%A A098455 Paul Barry (pbarry(AT)wit.ie), Sep 08 2004