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%I #18 Dec 15 2022 14:21:53
%S 1,6,80,3434
%N a(n) is the number of possible standard CMOS cells with a maximum of n stages.
%C My colleague, Hagen Sankowski, has independently verified the first few numbers and then stumbled across the paper from 1981.
%H Sankowski, <a href="https://github.com/chipforge/StdCellLib">GitHub repository of the StdCellLib software</a> which we are generating standard cells, which we used to re-discover the sequence with.
%H Uehara & Vancleemput, <a href="https://doi.org/10.1109/TC.1981.1675787">Optimal Layout of CMOS Functional Arrays</a>, IEEE Transactions on Computers, 1981, C-30(5), 305-312.
%e For n = 2 there are 6 possible different standard cells with a maximum of 2 stages.
%K nonn,more
%O 1,2
%A _Philipp Gühring_, Oct 26 2022