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A226268
Number of additive Z_2 Z_8 codes of a certain type (see Siap-Aydogdu for precise definition).
7
840, 52080, 2187360, 79369920, 2698577280, 88965999360, 2889276741120, 93139362032640, 2991417157048320, 95900970385059840, 3071643397494497280, 98337605476992860160, 3147523797281917992960, 100732289496652001771520, 3223617721482127290531840
OFFSET
1,1
COMMENTS
N2×8(r, r+2; 2, 0, 1, r) r>=2. (Siap-Aydogdu Table 1)
LINKS
I. Siap and I. Aydogdu, Counting The Generator Matrices of Z_2 Z_8 Codes, arXiv preprint arXiv:1303.6985 [math.CO], 2013.
MATHEMATICA
QP = QPochhammer;
a[n_] := (16^(n+1)(2^(n+3))^n (2^(n+3)-1) QP[2^(-2-n), 2, n+1] QP[2^(-1-n), 2, 2])/((2^(n+2))^n (3 QP[2^(-1-n), 2, n+1] 2^n));
Array[a, 15] (* Jean-François Alcover, Sep 01 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 02 2013
EXTENSIONS
Terms a(4) and beyond from Lars Blomberg, Jun 14 2017
STATUS
approved