login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A143696 Number of additive cyclic codes over GF(4) of length n that can be generated by one codeword. 1
4, 10, 24, 46, 72, 260, 400, 766, 1584, 2900, 4104, 19596, 16392, 67240, 139968, 196606, 266256, 1098760, 1048584, 3416604, 10454400, 10506260, 16810000, 83667116, 75497616, 167854100, 415239264, 1275614776, 1073741832, 6341140000, 6179217664, 12884901886 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
REFERENCES
W. C. Huffman, Additive cyclic codes over F_4, Advances in Math. Communication, 2 (2008), 309-343.
LINKS
FORMULA
See A143695 for formula.
PROG
(PARI) csiz(n, q) = {list = listcreate(n); A = vector(n); for (i=0, n-1, ai = i+1; if (!A[ai], ni = i; nai = ni+1; s = 0; while (! A[nai], A[nai] = 1; s++; ni = lift(Mod(ni*q, n)); nai = ni+1; ); listput(list, s); ); ); return (Vec(list)); } /* algorithm from arXiv:cs/0703129 */
a(n) = {expz = 2^valuation(n, 2); y = n/expz; d = csiz(y, 2); prod(i=1, length(d), 1 + (2^(expz*d[i])-1)*(2^d[i]+1)/(2^d[i]-1)); } \\ Michel Marcus, Mar 06 2013
CROSSREFS
Cf. A143695.
Sequence in context: A008251 A174934 A083168 * A058514 A182094 A291949
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 13 2008, based on email from W. C. Huffman
EXTENSIONS
More terms from Michel Marcus, Mar 06 2013
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 19 09:23 EDT 2024. Contains 371782 sequences. (Running on oeis4.)