A073971 Number of strings of length n over Z_6 with trace 0 and subtrace 0.

1, 1, 3, 18, 126, 1008, 8100, 52488, 297432, 1679616, 9843120, 59058720, 358108128, 2176782336, 13162730688, 78976384128, 471877757568, 2820249944064, 16891882995456, 101361597378048, 608764662139392, 3656158440062976, 21947909832446976, 131687458994681856

Offset

1,3

Links

Table of n, a(n) for n=1..24.

Max Alekseyev, PARI/GP scripts for miscellaneous math problems

F. Ruskey Strings over Z_6 with given trace and subtrace

Formula

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.

Crossrefs

Cf. A073972, A073973, A073974, A073975, A073976, A073977, A073978, A073979, A073980, A073981, A073982, A073983, A073984, A073985, A073986, A073987, A073988, A073989, A073990, A073991, A073992, A073993, A073994.

Sequence in context: A340894 A363560 A074557 * A366666 A369940 A264230

Adjacent sequences: A073968 A073969 A073970 * A073972 A073973 A073974

Keyword

easy,nonn

Author

Frank Ruskey, Nate Kube, Aug 16 2002

Extensions

Terms a(11) onward from Max Alekseyev, Apr 09 2013

Status

approved