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%I #4 Jul 15 2026 18:34:30
%S 1,2,5,15,53,228,1209,7747,58225,500544,4832313,51687383,606215565,
%T 7731822692,106508476905,1575578081523,24906716310217,418953742412128,
%U 7470858290454729,140766571939157751,2794339758909240773,58286364420483563796,1274476812220456366841,29150033296842803410371
%N Antidiagonal sums of the array A397775.
%F a(n) = Sum_{k=0..n} A397775(n-k, k).
%t A397775[0,k_]:=1; A397775[n_,k_]:=A397775[n,k]=n*A397775[n-1,k]+k; a[n_]:=Sum[A397775[n-k,k], {k,0,n}]; Array[a,24,0]
%Y Cf. A397775.
%K nonn,new
%O 0,2
%A _Stefano Spezia_, Jul 09 2026