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%I #20 Aug 13 2020 14:02:28
%S 1,0,-1,3,2,5,9,13,89,485,4891
%N a(n) is the index of the first occurrence of n in A249905, or -1 if n does not occur.
%C a(n) is the smallest number of Hamiltonian cycles up to direction which requires at least an n-vertex graph to realize.
%H Erich Friedman, <a href="https://erich-friedman.github.io/mathmagic/0912.html">Math Magic</a> (September 2012)
%K sign,hard,more
%O 1,4
%A _Jeremy Tan_, Nov 08 2014
%E a(10)-a(11) using data from _Johan de Ruiter_ added by _Jeremy Tan_, Nov 02 2018