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%I #10 Dec 24 2021 15:32:00
%S 0,48,28560,47045880,152587890624,819628286980800,6582952005840035280,
%T 73885357344138503765448,1104427674243920646305299200,
%U 21209401372879911350250244140624,508858109619679129936596364708525200
%N a(n) = (6*n + 1)^(2*n) - 1.
%C In Bátfai's notation, a(n) gives the total number of Turing machines with n states.
%H Norbert Bátfai, <a href="https://arxiv.org/abs/0908.1159">On the Running Time of the Shortest Programs</a>, arXiv:0908.1159 [cs.CC], Aug 10, 2009.
%t Table[(6n+1)^(2n)-1,{n,0,20}] (* _Harvey P. Dale_, Dec 24 2021 *)
%o (Maxima) makelist((6*n + 1)^(2*n) - 1, n, 0, 20); /* _Franck Maminirina Ramaharo_, Jan 15 2019 */
%Y Cf. A028444.
%K easy,nonn
%O 0,2
%A _Jonathan Vos Post_, Aug 11 2009
%E Edited and name clarified by _Franck Maminirina Ramaharo_, Jan 15 2019