%I A128419
%S A128419 1,4,25,168,1181,8524,62609,465616,3495013,26423604,200920985,
%T A128419 1534936440,11771854381,90578698396,698921030945,5406132020128,
%U A128419 41905249405301,325434733291396,2531523208218665,19721766268370248
%N A128419 Expansion of 8/(sqrt(1-8x)(sqrt(1-8x)+4x+7)).
%C A128419 Diagonal sums of number triangle A128417.
%F A128419 a(n)=sum{k=0..floor(n/2), 2^(n-2k)*C(2n-2k,n-2k)}
%Y A128419 Sequence in context: A079750 A073517 A074422 this_sequence A006880 A081068 
               A163072
%Y A128419 Adjacent sequences: A128416 A128417 A128418 this_sequence A128420 A128421 
               A128422
%K A128419 easy,nonn
%O A128419 0,2
%A A128419 Paul Barry (pbarry(AT)wit.ie), Mar 02 2007