login
Number of additive Z_2 Z_8 codes of a certain type (see Siap-Aydogdu for precise definition).
6

%I #22 Sep 01 2018 17:37:06

%S 504,486080,1360627200,13028011487232,461548202708533248,

%T 62904245232195703930880,33630170777556360030742118400,

%U 71219568024522244738221811324420096,600357043171015092778940374122700581371904,20193878525098148007889802657546998364965856870400

%N Number of additive Z_2 Z_8 codes of a certain type (see Siap-Aydogdu for precise definition).

%C N2×8(r+1, 2r+1; r, 0, r, r) r>=1. (Siap-Aydogdu Table 1)

%H Lars Blomberg, <a href="/A226266/b226266.txt">Table of n, a(n) for n = 1..30</a>

%H I. Siap and I. Aydogdu, <a href="http://arxiv.org/abs/1303.6985">Counting The Generator Matrices of Z_2 Z_8 Codes</a>, arXiv preprint arXiv:1303.6985 [math.CO], 2013.

%t QP = QPochhammer;

%t a[n_] := ((2^(2n + 1))^n (2^(3n + 2))^n (2^(5n + 3))^n QP[2^(-2n-1), 2, n] QP[2^(-n-1), 2, n]^2)/(2^n^2 (4^n)^n (8^n)^(2n) QP[2^(-n), 2, n]^3);

%t Array[a, 10] (* _Jean-François Alcover_, Sep 01 2018 *)

%Y Cf. A226262, A226263, A226264, A226265, A226267, A226268.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Jun 02 2013

%E Terms a(4) and beyond from _Lars Blomberg_, Jun 14 2017