A126487 Number of base 19 n-digit numbers with adjacent digits differing by three or less.

1, 19, 121, 791, 5217, 34587, 230033, 1533159, 10233063, 68367029, 457062389, 3057032825, 20453043685, 136869404619, 916044100681, 6131521065627, 41043887722493, 274756556545945, 1839334652522085, 12313523619477007

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+7^(n-1) for base>=3n-2; a(base,n)=a(base-1,n)+7^(n-1)-2 when base=3n-3.

Links

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

Formula

G.f.: (1+8*x-64*x^2-36*x^3+236*x^4+91*x^5-231*x^6-80*x^7+63*x^8+18*x^9) / (1-11*x+24*x^2+48*x^3-96*x^4-77*x^5+96*x^6+49*x^7-27*x^8-9*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]`-$[i+1]`>3)+($[i+1]`-$[i]`>3))

Crossrefs

Cf. Base 19 differing by two or less A126406, one or less A126373.

Sequence in context: A252054 A070302 A125329 * A241965 A182193 A109669

Adjacent sequences: A126484 A126485 A126486 * A126488 A126489 A126490

Keyword

nonn,base

Author

R. H. Hardin, Dec 27 2006

Status

approved