%I #14 Dec 30 2022 10:55:03

%S 1,3,3,7,-1,-8,-3,48,1,-39,-6,34,-25,-293,24,2649,-35,-2104,-239,3387,

%T 323,-15322,-182,27551,-2477,-121985,3663,275053,-360,-942231,-26801,

%U 8245538,40690,-7506845,11479,19149901,-297030,-61205072,442870,158934665,284075,-490800388,-3338212

%N Product_{n>=1} (1 + a(n) * x^n) = 1 + Sum_{n>=1} (n * (n + 1) / 2) * x^n.

%H Seiichi Manyama, <a href="/A359407/b359407.txt">Table of n, a(n) for n = 1..1000</a>

%Y Cf. A000217, A147559.

%K sign,look

%O 1,2

%A _Seiichi Manyama_, Dec 30 2022