A073991 Number of strings of length n over Z_6 with trace 3 and subtrace 2.

0, 4, 18, 48, 180, 1080, 7056, 44928, 286416, 1762560, 10349856, 60217344, 356638464, 2145709440, 12976433280, 78399995904, 472093588224, 2832561529344, 16960580969472, 101554796888064, 608733733690368, 3652526115938304, 21926115464435712, 131620960833896448

Offset

1,2

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. A073971, A073972, A073973, A073974, A073975, A073976, A073977, A073978, A073979, A073980, A073981, A073982, A073983, A073984, A073985, A073986, A073987, A073988, A073989, A073990, A073992, A073993, A073994.

Sequence in context: A259451 A181860 A027271 * A052642 A102928 A081528

Adjacent sequences: A073988 A073989 A073990 * A073992 A073993 A073994

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