%I #6 Jul 01 2023 12:11:18
%S 1,2,5,21,129,1099,11647,148292,2190302,36842892,694276152,
%T 14488348603,331537914373,8254117606799,222087256536602,
%U 6421589319659283,198565371839434761,6538245667687424041,228396692050813678534,8436237099236470594589
%N Row sums of triangle A144270 (called S2hat(-1)).
%F a(n) = Sum_{m=1..n} A144270(n,m), n>=1.
%Y Cf. A144270.
%K nonn,easy
%O 1,2
%A _Wolfdieter Lang_, Oct 09 2008