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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

Table of n, a(n) for n=0..18.

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-Fran├žois 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

N. J. A. Sloane.

EXTENSIONS

More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jul 04 2000

STATUS

approved

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Last modified October 17 07:57 EDT 2018. Contains 316276 sequences. (Running on oeis4.)