A002495 Theta series of 27-dimensional unimodular lattice with root system A_1 with no parity vector of norm 3.

1, 0, 2, 2676, 101118, 1644784, 16044996, 110148864, 584716268, 2549726784, 9515920164, 31314134428, 92917720104, 252775518960, 638328487880, 1511740834560, 3387163064214, 7228599229760, 14768913424614, 29023937463900, 55107648867544, 101434033397472

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

References

• R. Bacher and B. B. Venkov, Réseaux entiers unimodulaires sans racine en dimension 27 et 28, in Réseaux euclidiens, designs sphériques et formes modulaires, pp. 212-267, Enseignement Math., Geneva, 2001.

Links

• R. Bacher and B. B. Venkov, Réseaux entiers unimodulaires sans racine en dimension 27 et 28

Crossrefs

Cf. A000122, A002408, A002434, A002490.

Formula

G.f.: theta3^27 - 54*theta3^19*delta8 + 218*theta3^11*delta8^2 where theta3 = A000122 and delta8 = A002408. - Sean A. Irvine, Feb 28 2020

Extensions

More terms from Sean A. Irvine, Feb 28 2020