A126509 Number of base 14 n-digit numbers with adjacent digits differing by four or less.

1, 14, 106, 834, 6626, 52818, 421418, 3363330, 26844922, 214272194, 1710301706, 13651507570, 108965442842, 869755228898, 6942331285450, 55413250676370, 442305075971450, 3530451257562498, 28179839583470762, 224929704767724786

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4.

Links

Table of n, a(n) for n=0..19.

Formula

G.f.: (1+5*x-16*x^2-30*x^3+14*x^4+20*x^5) / (1-9*x+4*x^2+34*x^3-6*x^4-20*x^5) (conjectured). - Colin Barker, Jul 18 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))

Crossrefs

Cf. Base 14 differing by three or less A126482, two or less A126401, one or less A126368.

Sequence in context: A206761 A190868 A125351 * A200056 A206754 A099300

Adjacent sequences: A126506 A126507 A126508 * A126510 A126511 A126512

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved