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%I #9 Jun 16 2019 08:05:29
%S 1,3,7,11,26,42,99,107,382,428,1156,1223,4525,4903,14811,14827,58022,
%T 61236,201420,201611
%N Number of nonterminal symbols in a certain "divide-and-conquer" context-free grammar in Chomsky normal form that generates all permutations of n symbols.
%H P. R. J. Asveld, <a href="http://dx.doi.org/10.1016/j.tcs.2005.11.010">Generating all permutations by context-free grammars in Chomsky normal form</a>, Theoretical Computer Science 354 (2006) 118-130.
%F a(n) = Sum_{k=1..n} t(n, k), where t(n, k) is the n-th row of the Pascal-like triangle of A090349.
%e a(4) = 4 + 6 + 0 + 1 = 11; cf. the example grammar of A090349.
%Y Cf. A090349.
%K nonn,more
%O 1,2
%A _Peter R. J. Asveld_, Jan 30 2004
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