A125478 - OEIS

A125478

Number of base 21 circular n-digit numbers with adjacent digits differing by 9 or less.

1, 21, 309, 3981, 58209, 868821, 13158381, 200564553, 3066826521, 46965700983, 719758889369, 11034259358429, 169188489197421, 2594373411616371, 39784176772781379, 610092929210756481, 9355893865558473961

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OFFSET

0,2

COMMENTS

[Empirical] a(base,n)=a(base-1,n)+F(9) for base>=9.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]`-$[(i+1)mod N]`>9)+($[(i+1)mod N]`-$[i]`>9))

CROSSREFS

Sequence in context: A025929 A021244 A183463 * A018054 A021484 A198376

Adjacent sequences: A125475 A125476 A125477 * A125479 A125480 A125481

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved