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%I A029671 #24 Jul 17 2014 21:52:59
%S A029671 1,2,6,8,6,8,4,8,18,10,4,20,16,0,12,16,14,16,18,12,24,8,12,32,12,14,2,
%T A029671 32,20,16,16,8,42,16,8,40,30,16,28,0,12,12,24,32,40,24,8,40,32,14,30,
%U A029671 32,0,40,16,16,36,24,20,44,40,8,28,40,30,4,16,44,48,16,16,40,54,12,28,40,24
%N A029671 Theta series of quadratic form with Gram matrix [ 2, 1, 0; 1, 4, 1; 0, 1, 4 ].
%C A029671 This is the monoclinic P lattice (the even holotype) of dimension 3.
%H A029671 John Cannon, <a href="/A029671/b029671.txt">Table of n, a(n) for n = 0..5000</a>
%H A029671 G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/monoclinicPe.html">Home page for this lattice</a>
%e A029671 1 + 2*x + 6*x^2 + 8*x^3 + 6*x^4 + 8*x^5 + 4*x^6 + 8*x^7 + 18*x^8 + ...
%e A029671 1 + 2*q^2 + 6*q^4 + 8*q^6 + 6*q^8 + 8*q^10 + 4*q^12 + 8*q^14 + 18*q^16 + 10*q^18 + ...
%o A029671 (PARI) {a(n) = if( n<1, n==0, qfrep( [ 2, 1, 0; 1, 4, 1; 0, 1, 4], n, 1)[n] * 2 )} /* _Michael Somos_, Apr 05 2012 */
%K A029671 nonn
%O A029671 0,2
%A A029671 _N. J. A. Sloane_.

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