%I #6 May 10 2022 14:26:32
%S 1,0,-1,4,-11,66,-547,4880,-27351,263310,-3258663,39791016,-390445563,
%T 5477278548,-84140635815,1486404086016,-18431412645519,
%U 322018685539542,-6436900596281679,133183534639917240,-2208721087854287811,49383164607876494604,-1149793471388581053219
%N Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + arcsinh(x).
%t nn = 23; f[x_] := Product[(1 + a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - ArcSinh[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten
%Y Cf. A001818, A006973, A137852, A353608, A353818, A353820, A353821.
%K sign
%O 1,4
%A _Ilya Gutkovskiy_, May 08 2022