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Absolute values of a certain cubic form at integer points (see Formula).
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%I #6 Jul 31 2024 20:34:16

%S 1,7,8,13,27,29,41,43,49,56,64,71,83,91,97,104,113,125,127,139,167,

%T 169,181,189,197,203,211,216,223,232,239,251,281,287,293,301,307,328,

%U 337,343,344,349,351,377,379,392,419,421,433,448,449,461,463,491,497,503

%N Absolute values of a certain cubic form at integer points (see Formula).

%C This sequence appears on p. 284 of Bryuno and Parusnikov, but the term 49 is missing. - _Sean A. Irvine_, Jul 31 2024

%D A. D. Bryuno and V. I. Parusnikov, Comparison of various generalizations of continued fractions, Mat. Zametki, 61 (No. 3, 1997), 339-348; English translation in Math. Notes, 61 (1997), 278-286.

%F {abs((L1.X)*(L2.X)*(L3.X)): X in Z^3} where "." denotes dot product and L1=(1,-c3,-1-c2), L2=(1,-c1,-1-c3), L3=(1,-c2,-1-c1) with c1=2*cos(6*Pi/7), c2=2*cos(4*Pi/7), c3=2*cos(2*Pi/7). - _Sean A. Irvine_, Jul 31 2024

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Apr 24 2001

%E Missing 49 and more terms from _Sean A. Irvine_, Jul 31 2024