A125433 Number of base 21 circular n-digit numbers with adjacent digits differing by 7 or less.

1, 21, 259, 2709, 32627, 401401, 5043115, 64108009, 821245795, 10571373945, 136492942139, 1765686281633, 22868116742483, 296391829451401, 3843261172758763, 49848967431027409, 646678407486881219

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+F(7) for base>=7.int(n/2)+1 and F(d) is the largest coefficient in (1+x+...+x^(2d))^n

Links

Table of n, a(n) for n=0..16.

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>7)+($[(i+1)mod N]`-$[i]`>7))

Crossrefs

Sequence in context: A322500 A241632 A323972 * A135122 A231380 A045505

Adjacent sequences: A125430 A125431 A125432 * A125434 A125435 A125436

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved