A124935 Number of base 18 circular n-digit numbers with adjacent digits differing by 2 or less.

1, 18, 84, 312, 1352, 5908, 26490, 120278, 552032, 2553972, 11892734, 55672118, 261759734, 1235323302, 5848421012, 27764530552, 132124679472, 630077734772, 3010344270942, 14406602755262, 69048608938842, 331383832210022

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.

See A285280 for confirmation of linear recurrence and code to produce sequence. - Ray Chandler, Aug 12 2023.

Links

Ray Chandler, Table of n, a(n) for n = 0..99

Index entries for linear recurrences with constant coefficients, signature (18, -120, 320, 14, -1624, 1767, 2860, -4610, -2408, 4913, 1016, -2500, -200, 580, 16, -48).

Prog

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

Crossrefs

Cf. Row 18 of A285280.

Sequence in context: A043961 A067984 A281372 * A126405 A250101 A141842

Adjacent sequences: A124932 A124933 A124934 * A124936 A124937 A124938

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved