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 A008445 Theta series of A_5 lattice. 5
 1, 30, 90, 140, 270, 360, 330, 660, 810, 570, 1020, 1260, 1100, 1560, 1620, 1452, 2190, 2340, 1710, 2940, 3240, 1920, 3360, 3960, 2970, 3930, 4140, 3920, 5460, 4680, 3360, 5940, 6570, 4620, 6180, 7560, 5130, 7320, 7920, 5280, 9180, 8100, 6600, 10500, 9900 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 110. LINKS John Cannon, Table of n, a(n) for n = 0..5000 LMFDB, Integral Lattice A5. EXAMPLE 1 + 30*q^2 + 90*q^4 + 140*q^6 + 270*q^8 + 360*q^10 + 330*q^12 + 660*q^14 + 810*q^16 + 570*q^18 + 1020*q^20 + 1260*q^22 + 1100*q^24 + 1560*q^26 + 1620*q^28 + 1452*q^30 + 2190*q^32 + 2340*q^34 + 1710*q^36 + 2940*q^38 + 3240*q^40 + 1920*q^42 + 3360*q^44 + 3960*q^46 + 2970*q^48 + ... MATHEMATICA terms = 45; f[q_] = LatticeData["A5", "ThetaSeriesFunction"][-I Log[q]/Pi]; s = Series[f[q], {q, 0, 2 terms}]; CoefficientList[s, q^2][[1 ;; terms]] (* Jean-François Alcover, Jul 04 2017 *) PROG (MAGMA) L:=Lattice("A", 5); T1 := ThetaSeries(L, 120); (PARI) seq(N) = {   my(q=[2, -1, 0, 0, 0; -1, 2, -1, 0, 0; 0, -1, 2, -1, 0;         0, 0, -1, 2, -1; 0, 0, 0, -1, 2]);   concat(1, 2*Vec(qfrep(q, N-1, 1))); }; seq(45) \\ Gheorghe Coserea, Nov 25 2018 CROSSREFS Sequence in context: A126384 A025417 A081807 * A039462 A138018 A004995 Adjacent sequences:  A008442 A008443 A008444 * A008446 A008447 A008448 KEYWORD nonn AUTHOR STATUS approved

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Last modified January 29 07:03 EST 2020. Contains 331337 sequences. (Running on oeis4.)