A125331 Number of base 21 circular n-digit numbers with adjacent digits differing by 3 or less.

1, 21, 135, 693, 4159, 25291, 157635, 995659, 6357119, 40921479, 265145505, 1727138841, 11300204035, 74208972755, 488874737353, 3229363648333, 21382430152111, 141869013922279, 942972599847861, 6277675948529895

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+A025012(n+1) for base>=3.int(n/2)+1

Links

Table of n, a(n) for n=0..19.

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>3)+($[(i+1)mod N]`-$[i]`>3))

Crossrefs

Sequence in context: A328861 A243201 A264554 * A126489 A033595 A220388

Adjacent sequences: A125328 A125329 A125330 * A125332 A125333 A125334

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved