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Number of strings of length n over Z_6 with trace 0 and subtrace 2.
22

%I #16 May 02 2019 11:08:23

%S 0,2,6,24,180,1440,9072,50544,286416,1658880,9722592,58335552,

%T 356638464,2179768320,13180786560,79012495872,472093588224,

%U 2821539889152,16894457846784,101356447675392,608733733690368,3656096522698752,21947538146863104,131685228881178624

%N Number of strings of length n over Z_6 with trace 0 and subtrace 2.

%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/TSstringZ6">Strings over Z_6 with given trace and subtrace</a>

%F a(n; t, s) = a(n-1; t, s) + a(n-1; t+5, s+5t+1) + a(n-1; t+4, s+4t+4) + a(n-1; t+3, s+3t+3) + a(n-1; t+2, s+2t+2) + a(n-1; t+1, s+t+1) where t is the trace and s is the subtrace.

%Y Cf. A073971, A073972, A073974, A073975, A073976, A073977, A073978, A073979, A073980, A073981, A073982, A073983.

%Y Cf. A073984, A073985, A073986, A073987, A073988, A073989, A073990, A073991, A073992, A073993, A073994.

%K easy,nonn

%O 1,2

%A _Frank Ruskey_ and Nate Kube, Aug 16 2002

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