%I #2 Mar 31 2012 13:20:14
%S 1,20,295,3485,33496,247799,1010905,-7422100,-238118825,-3513857515,
%T -38530770320,-329008652665,-1926925302575,-594574697500,
%U 188633380315975,3451130126965325,42502627523897800,406764806549554775,2912899847916711625
%N Alternating row sums of triangle A132166 (s1(7)).
%F a(n)=sum(A132166(n,m)*(-1)^(m-1),m=1..n), n>=1.
%F O.g.f.: g(x)/(1+g(x)) with g(x)=(1-(1-6*x)^6)/(36*(1-6*x)^6), o.g.f. first column of A132166.
%Y Cf. A132167 (row sums of A132166).
%K sign,easy
%O 1,2
%A _Wolfdieter Lang_ Oct 12 2007