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a(n) = A178901(n)/n.
0

%I #26 Dec 21 2020 07:36:53

%S 2,2,2,3,4,6,10,17,30,54,98,179,330,612,1142,2141,4030,7612,14422,

%T 27401,52192,99639,190613,365341,701454,1348950,2597977,5010384,

%U 9675224,18705433,36204063,70145372,136039509,264076693,513063289,997623061,1941320551,3780466336

%N a(n) = A178901(n)/n.

%e a(4) = A178901(4)/4 = 12/4 = 3.

%o (PARI) lista(nn) = {my(va = vector(nn)); va[1] = 2; for (n=2, nn, va[n] = (2*(n-1)*va[n-1]\n);); va;} \\ _Michel Marcus_, Dec 18 2020

%Y Cf. A178901.

%K nonn

%O 1,1

%A _J. Lowell_, Dec 16 2020