A126537 Number of base 16 n-digit numbers with adjacent digits differing by five or less.

1, 16, 146, 1386, 13276, 127470, 1224594, 11766272, 113057850, 1086341506, 10438376428, 100299731078, 963754991066, 9260480594912, 88981641951426, 855002344551114, 8215503709753468, 78940720623107646, 758521643084139202

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+11^(n-1) for base>=5n-4; a(base,n)=a(base-1,n)+11^(n-1)-2 when base=5n-5.

Links

Table of n, a(n) for n=0..18.

Formula

G.f.: (1+5*x-21*x^2-30*x^3+44*x^4+20*x^5-20*x^6) / (1-11*x+9*x^2+46*x^3-36*x^4-28*x^5+20*x^6) (conjectured). - Colin Barker, Jul 18 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>5)+($[i+1]`-$[i]`>5))

Crossrefs

Cf. Base 16 differing by four or less A126511, three or less A126484, two or less A126403, one or less A126370.

Sequence in context: A027651 A125379 A232063 * A252818 A232957 A214513

Adjacent sequences: A126534 A126535 A126536 * A126538 A126539 A126540

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved