A109146 G.f.: square root of theta series of lattice in A004535.

1, 0, 126, 1568, 756, -165312, -1227240, 19894464, 414106686, -456317568, -96106099320, -809737207776, 15047550684488, 345938324437440, -318788546956992, -91256560218798912, -842108390970746508, 15331399952805675648, 380895013380314119302, -178390965727200705696

Offset

0,3

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..800

N. Heninger, E. M. Rains and N. J. A. Sloane, On the Integrality of n-th Roots of Generating Functions, J. Combinatorial Theory, Series A, 113 (2006), 1732-1745.

Mathematica

terms = 20; t2 = EllipticTheta[2, 0, q]; t3 = EllipticTheta[3, 0, q]; s = Sqrt[(t3^7 + 7*t3^3*t2^4)^2 + (t2^7 + 7*t2^3*t3^4)^2] + O[q]^terms // Normal; Join[{1, 0}, Rest[(List @@ s) /. q -> 1]][[1 ;; terms]] (* Jean-François Alcover, Jul 08 2017 *)

Crossrefs

Sequence in context: A297657 A027805 A027814 * A249197 A249212 A249319

Adjacent sequences: A109143 A109144 A109145 * A109147 A109148 A109149

Keyword

sign

Author

N. J. A. Sloane and Nadia Heninger, Aug 18 2005

Status

approved