A073965 - OEIS

%I #23 May 03 2019 07:17:23

%S 0,0,6,30,150,650,3150,15500,78000,390000,1952500,9762500,48831250,

%T 244156250,1220781250,6103593750,30517656250,152587500000,

%U 762939062500,3814695312500,19073484375000,95367421875000,476837167968750,2384185839843750,11920929199218750

%N Number of strings of length n over Z_5 with trace 0 and subtrace 2.

%C Same as the number of strings of length n over Z_5 with trace 0 and subtrace 3.

%C Same as the number of strings of length n over GF(5) with trace 0 and subtrace 2.

%C Same as the number of strings of length n over GF(5) with trace 0 and subtrace 3.

%C Same as the number of strings of length n over GF(5) with trace 1 and subtrace 0.

%C Same as the number of strings of length n over GF(5) with trace 4 and subtrace 0.

%H Max Alekseyev, <a href="http://home.gwu.edu/~maxal/gpscripts/">PARI/GP scripts for miscellaneous math problems</a>

%H F. Ruskey, <a href="http://combos.org/TSstringZ5">Strings over Z_5 with given trace and subtrace</a>

%H F. Ruskey, <a href="http://combos.org/TSstringF5">Strings over GF(5) with given trace and subtrace</a>

%F a(n; t, s) = a(n-1; t, s) + a(n-1; t+4, s+4t+1) + a(n-1; t+3, s+3t+4) + a(n-1; t+2, s+2t+4) + a(n-1; t+1, s+t+1).

%F Empirical g.f.: 2*x^3*(50*x^4-50*x^3+30*x^2-15*x+3) / ((5*x-1)*(5*x^2-1)*(25*x^4-25*x^3+15*x^2-5*x+1)). - _Colin Barker_, Apr 03 2015

%Y Cf. A073963, A073964, A073966, A073967, A073968, A073969, A073970.

%K easy,nonn

%O 1,3

%A _Frank Ruskey_, Nate Kube, Aug 15 2002

%E Terms a(11) onward from _Max Alekseyev_, Apr 09 2013