A126399 Number of base 12 n-digit numbers with adjacent digits differing by two or less.

1, 12, 54, 250, 1168, 5486, 25848, 122024, 576748, 2728038, 12909648, 61108496, 289310874, 1369855464, 6486547342, 30716393200, 145458062754, 688830120102, 3262050022332, 15447978818780, 73156731187376, 346447866034700

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+5^(n-1) for base>=2n-1; a(base,n)=a(base-1,n)+5^(n-1)-2 when base=2n-2.

Links

Table of n, a(n) for n=0..21.

Formula

G.f.: (1+5*x-22*x^2-17*x^3+21*x^4+7*x^5-4*x^6) / (1-7*x+8*x^2+15*x^3-9*x^4-5*x^5+2*x^6) (conjectured). - Colin Barker, Jul 17 2017

Prog

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

Crossrefs

Cf. Base 12 differing by one or less A126366.

Sequence in context: A005549 A124858 A183713 * A137938 A009726 A230920

Adjacent sequences: A126396 A126397 A126398 * A126400 A126401 A126402

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved