A073981 Number of strings of length n over Z_6 with trace 1 and subtrace 4.

0, 2, 9, 24, 126, 972, 7056, 46656, 297432, 1806624, 10478160, 60466176, 356638464, 2142770112, 12958657344, 78328332288, 471877757568, 2832129868032, 16960580969472, 101559956668416, 608764662139392, 3652649829734400, 21926486787222528, 131621703842267136

Offset

1,2

Comments

Same as the number of strings of length n over Z_6 with trace 5 and subtrace 4.

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.

Example

a(2;5,4)=2 since the two 6-ary strings of trace 5, subtrace 4 and length 2 are { 14, 41 }.

Crossrefs

Cf. A073971, A073972, A073973, A073974, A073975, A073976, A073977, A073978, A073979, A073980, A073982, A073983, A073984, A073985, A073986, A073987, A073988, A073989, A073990, A073991, A073992, A073993, A073994.

Sequence in context: A213720 A378070 A353822 * A006973 A137852 A347106

Adjacent sequences: A073978 A073979 A073980 * A073982 A073983 A073984

Keyword

easy,nonn

Author

Frank Ruskey and Nate Kube, Aug 16 2002

Extensions

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

Status

approved