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A029671
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Theta series of quadratic form with Gram matrix [ 2, 1, 0; 1, 4, 1; 0, 1, 4 ].
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1
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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, 32, 20, 16, 16, 8, 42, 16, 8, 40, 30, 16, 28, 0, 12, 12, 24, 32, 40, 24, 8, 40, 32, 14, 30, 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
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OFFSET
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0,2
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COMMENTS
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This is the monoclinic P lattice (the even holotype) of dimension 3.
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LINKS
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EXAMPLE
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1 + 2*x + 6*x^2 + 8*x^3 + 6*x^4 + 8*x^5 + 4*x^6 + 8*x^7 + 18*x^8 + ...
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 + ...
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PROG
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(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 */
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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