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Diagonal sums of number triangle A107030.
1

%I #3 Mar 30 2012 18:59:07

%S 1,2,3,4,7,12,25,56,145,422,1389,5072,20283,87996,412663,2087868,

%T 11361831,66155642,409567833,2680486870,18465061963,133504614880,

%U 1011121118741,8008145020804,66201411633209,570006877641976

%N Diagonal sums of number triangle A107030.

%F a(n)=sum{k=0..floor(n/2), (k-1)*C(k(n-2k), n-2k)-(k-2)*sum{j=0..n-k, C(k(n-2k), j)}}

%K easy,nonn

%O 0,2

%A _Paul Barry_, May 09 2005