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%I #7 Dec 13 2013 13:58:13
%S 1,4,21,358,92007,6029862760,25898063359598159721,
%T 477734946799221833229035410333259818858,
%U 162564778457687820218065957445498785826947155451688293007128627114802460256107
%N a(0)=1, a(n+1)=1+(2^(2^n)+1)*a(n).
%C a(n) = height of lattice of orthogonal arrays with 2^2^n runs.
%H E. M. Rains, N. J. A. Sloane and J. Stufken, The Lattice of N-Run Orthogonal Arrays, J. Stat. Planning Inference, 102 (2002), 477-500 (<a href="http://neilsloane.com/doc/rao.txt">Abstract</a>, <a href="http://neilsloane.com/doc/rao.pdf">pdf</a>, <a href="http://neilsloane.com/doc/rao.ps">ps</a>)
%F a(n) converges to nearest integer to c*(2^(2^n)-1), where c = 1.403936827882178... (see A048649).
%t RecurrenceTable[{a[0]==1,a[n]==1+(2^(2^(n-1))+1)a[n-1]},a,{n,10}] (* _Harvey P. Dale_, Dec 13 2013 *)
%Y Cf. A039930, A048638.
%K nonn,nice,easy
%O 0,2
%A _N. J. A. Sloane_, E. M. Rains
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