A126404 Number of base 17 n-digit numbers with adjacent digits differing by two or less.

1, 17, 79, 375, 1793, 8611, 41473, 200149, 967355, 4680655, 22667487, 109848049, 532610303, 2583482303, 12535495657, 60839746967, 295338090269, 1433900817213, 6962605102325, 33811619587041, 164207415391765

Offset

1,2

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=1..21.

Formula

G.f.: (1+7*x-64*x^2+48*x^3+171*x^4-100*x^5-120*x^6+50*x^7+20*x^8-6*x^9) / (1-10*x+27*x^2+4*x^3-73*x^4+19*x^5+50*x^6-14*x^7-8*x^8+2*x^9) (conjectured). - Colin Barker, Jul 18 2017

Prog

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

Crossrefs

Cf. Base 17 differing by one or less A126371.

Sequence in context: A357740 A124898 A036429 * A142021 A353937 A172045

Adjacent sequences: A126401 A126402 A126403 * A126405 A126406 A126407

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Extensions

Edited by Charles R Greathouse IV, Aug 02 2010

Status

approved