A073977 Number of strings of length n over Z_6 with trace 1 and subtrace 0.

1, 4, 9, 36, 180, 972, 6300, 44928, 297432, 1784592, 10349856, 60466176, 358108128, 2145709440, 12958657344, 78364164096, 472093588224, 2832129868032, 16957996040448, 101554796888064, 608764662139392, 3652587972836352, 21926115464435712, 131621703842267136

Offset

1,2

Comments

Same as the number of strings of length n over Z_6 with trace 5 and subtrace 0.

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, A073978, A073979, A073980, A073981, A073982, A073983, A073984, A073985, A073986, A073987, A073988, A073989, A073990, A073991, A073992, A073993, A073994.

Sequence in context: A118548 A176830 A077211 * A055872 A066924 A251689

Adjacent sequences: A073974 A073975 A073976 * A073978 A073979 A073980

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