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%I #24 Oct 14 2018 12:15:20
%S 1,1,1,1,1,2,1,2,3,2,3,2,4,2,1,5,2,2,4,4,3,1,4,7,5,3,4,6,2,2,8,5,6,3,
%T 8,2,6,10,4,2,5,5,4,4,3,10,2,7,6,4,10,1,8,11,4,5,8,4,2,13,4,9,4,3,6,
%U 14,4,7,5,4,12,2,2,15,6,6,8,7,12,4,8,13,8,2,11,8,4,3,14,4,4,8,10,8
%N Duplicate of A006641.
%C Same as A006641. - _Georg Fischer_, Oct 12 2018
%F Class number of A003657(n).
%t FundamentalDiscriminantQ[n_Integer] := n != 1 && (Mod[n, 4] == 1 || !Unequal[ Mod[n, 16], 8, 12]) && SquareFreeQ[n/2^IntegerExponent[n, 2]] (* via _Eric W. Weisstein_ *);
%t NumberFieldClassNumber@ Sqrt@ # & /@ Select[-Range@ 300, FundamentalDiscriminantQ]
%o (PARI) for(n=1, 300, if(isfundamental(-n), print1(quadclassunit(-n).no, ", "))) \\ _Andrew Howroyd_, Jul 23 2018
%Y Cf. A191410.
%K dead
%O 1,6
%A _Robert G. Wilson v_, Jun 01 2011
%E Terms corrected by _Andrew Howroyd_ and _Robert G. Wilson v_, Jul 24 2018
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