A126363 Number of base 9 n-digit numbers with adjacent digits differing by one or less.

1, 9, 25, 71, 203, 583, 1679, 4845, 14001, 40503, 117263, 339699, 984515, 2854281, 8277153, 24007543, 69642819, 202046535, 586220911, 1700972653, 4935747673, 14322646039, 41562779655, 120613013891, 350017652003, 1015758270153

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1

Links

Table of n, a(n) for n=0..25.

Formula

Empirical G.f.: -(2*x^5+13*x^4-4*x^3-15*x^2+4*x+1) / ((x-1)*(x^4+6*x^3+x^2-4*x+1)). [Colin Barker, Nov 26 2012]

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>1)+($[i+1]`-$[i]`>1))

Crossrefs

Sequence in context: A146589 A146866 A271731 * A036836 A125997 A199111

Adjacent sequences: A126360 A126361 A126362 * A126364 A126365 A126366

Keyword

nonn,base

Author

R. H. Hardin, Dec 26 2006

Status

approved