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%I #5 Mar 30 2012 18:36:44
%S 0,1,-1,-5,-20,-51,-289,-1426,-22622,-259734,-15968025,-405699154,
%T -110016092396,-6660687936224,-7918107904514781,-1332064204800175993,
%U -6282110941080800842150,-3412055538464918268114551,-57520868453379641772222723912
%N Column 1 of triangular matrix A102225, in which row k is formed from the first differences of row (k-1) of its matrix square (A102228).
%F a(n) = A102229(n-1) - A102226(n) for n>=2, where A102226 equals column 0 of A102225 and A102229 equals column 1 of A102228.
%o (PARI) {a(n)=local(A=matrix(2,2),B);A[1,1]=1; for(m=2,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=1,if(j==1,B[i,j]=(A^2)[i-1,1], B[i,j]=(A^2)[i-1,j]-(A^2)[i-1,j-1]));));A=B);return(A[n+1,2])}
%Y Cf. A102225, A102226, A102228, A102229.
%K sign
%O 0,4
%A _Paul D. Hanna_, Jan 01 2005
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