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 A256856 Theta series of 4-dimensional 21-modular lattice A2xT7 with minimal norm 4. 0
 1, 0, 6, 0, 12, 12, 6, 24, 18, 0, 24, 12, 12, 24, 66, 12, 48, 36, 6, 24, 60, 24, 60, 36, 18, 48, 60, 0, 156, 48, 24, 48, 102, 12, 72, 132, 12, 48, 96, 24, 144, 60, 66, 72, 132, 12, 108, 72, 48, 168, 138, 36, 144, 72, 6, 120, 342, 24, 132, 72, 60, 96, 144, 24 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..63. G. Nebe and N. J. A. Sloane, Home page for this lattice EXAMPLE G.f. = 1 + 6*x^2 + 12*x^4 + 12*x^5 + 6*x^6 + 24*x^7 + 18*x^8 + 24*x^10 + ... G.f. = 1 + 6*q^4 + 12*q^8 + 12*q^10 + 6*q^12 + 24*q^14 + 18*q^16 + 24*q^20 + ... PROG (PARI) {a(n) = if( n<0, 0, polcoeff( 1 + 2 * x * Ser( qfrep( [4, 2, 2, 1; 2, 4, 1, 2; 2, 1, 8, 4; 1, 2, 4, 8], n, 1)), n))}; (Magma) A := Basis( ModularForms( Gamma0(21), 2), 64); A[1] + 6*A[3]; CROSSREFS Sequence in context: A028619 A062765 A137946 * A028603 A205966 A183772 Adjacent sequences: A256853 A256854 A256855 * A256857 A256858 A256859 KEYWORD nonn AUTHOR Michael Somos, Apr 12 2015 STATUS approved

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Last modified August 5 17:52 EDT 2024. Contains 374954 sequences. (Running on oeis4.)