A126365 Number of base 11 n-digit numbers with adjacent digits differing by one or less.

1, 11, 31, 89, 257, 745, 2165, 6303, 18375, 53625, 156629, 457795, 1338779, 3916897, 11463989, 33563035, 98286811, 287884769, 843365485, 2471005371, 7240717539, 21219286113, 62189049541, 182274146987, 534268171099

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..24.

Formula

Empirical G.f.: -(6*x^6+4*x^5-34*x^4-6*x^3+26*x^2-5*x-1) / ((x^2+2*x-1)*(2*x^4-4*x^3-2*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: A072673 A250461 A259508 * A082102 A199112 A299782

Adjacent sequences: A126362 A126363 A126364 * A126366 A126367 A126368

Keyword

nonn,base

Author

R. H. Hardin, Dec 26 2006

Status

approved