|
Search: id:A073997
|
|
|
| A073997 |
|
Number of strings of length n over GF(4) with trace 1 and subtrace 0. |
|
+0
5
|
|
| 1, 2, 3, 16, 76, 272, 1008, 4096, 16576, 65792, 261888, 1048576, 4197376, 16781312, 67104768
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
Same as the number of strings of length n over GF(4) with trace x and subtrace 0 where x=RootOf(z^2+z+1). Same as the number of strings of length n over GF(4) with trace y and subtrace 0 where y=1+x.
|
|
LINKS
|
F. Ruskey Number of strings over GF(4) of given trace and subtrace
|
|
FORMULA
|
a(n; t, s) = a(n-1; t, s) + a(n-1; t-1, s-(t-1)) + a(n-1; t-2, s-2(t-2)) + a(n-1; t-3, s-3(t-3)) where t is the trace and s is the subtrace. Note that all operations involving operands t or s are carried out over GF(4).
G.f.: -(2*q^3-3*q^2+4*q-1)*q/[(1-2q)(1-4q)(1+4q^2)]. - Lawrence Sze, Oct 24 2004
|
|
CROSSREFS
|
Cf. A073995, A073996, A073998, A073999, A074000.
Adjacent sequences: A073994 A073995 A073996 this_sequence A073998 A073999 A074000
Sequence in context: A103331 A052506 A052858 this_sequence A007118 A012572 A067848
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Frank Ruskey, Nate Kube (fruskey(AT)cs.uvic.ca), Aug 16 2002
|
|
|
Search completed in 0.002 seconds
|
