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 A002520 Theta series of 28-dimensional unimodular lattice with no roots and with no parity vector of norm 4. 2
 1, 0, 0, 2240, 98280, 1790208, 19138560, 141920640, 805208040, 3723722240, 14651449344, 50573436480, 156717687840, 443691198720, 1162883174400, 2851049534592, 6596666916840, 14509544394240, 30507984568320 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 REFERENCES R. Bacher and B. B. Venkov, Reseaux entiers unimodulaires sans racine en dimension 27 et 28, in Reseaux euclidiens, designs spheriques et formes modulaires, pp. 212-267, Enseignement Math., Geneva, 2001. LINKS R. Bacher and B. B. Venkov, Reseaux entiers unimodulaires sans racine en dimension 27 et 28 (html, ps). FORMULA t3^28-56*t3^20*D8+280*t3^12*D8^2 where t3=theta_3(z) and D8=(theta_2(z)*theta_4(z))^4/16. MATHEMATICA terms = 19; t3[z_] := EllipticTheta[3, 0, z]; D8[z_] := (EllipticTheta[2, 0, z]*EllipticTheta[4, 0, z])^4/16; s = t3[z]^28 - 56*t3[z]^20*D8[z] + 280*t3[z]^12*D8[z]^2 + O[z]^terms; CoefficientList[s, z] (* Jean-François Alcover, Jul 05 2017 *) CROSSREFS Cf. A002519. Sequence in context: A079013 A186865 A038728 * A183771 A271470 A263912 Adjacent sequences:  A002517 A002518 A002519 * A002521 A002522 A002523 KEYWORD nonn,nice,easy AUTHOR EXTENSIONS More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jul 04 2000 STATUS approved

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Last modified June 17 18:04 EDT 2019. Contains 324198 sequences. (Running on oeis4.)