A124949 Number of base 21 circular n-digit numbers with adjacent digits differing by 2 or less.

1, 21, 99, 369, 1607, 7051, 31743, 144683, 666527, 3094947, 14463569, 67946603, 320593259, 1518250599, 7212838277, 34360479199, 164079145839, 785173661987, 3764380920489, 18077996769707, 86948519336037, 418760656546517

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 (21, -171, 627, -595, -2635, 6891, 1703, -19279, 6565, 26454, -13848, -20145, 11191, 8590, -4346, -1925, 775, 190, -50, -5, 1).

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 21 of A285280.

Sequence in context: A288750 A178794 A140370 * A267681 A126408 A157329

Adjacent sequences: A124946 A124947 A124948 * A124950 A124951 A124952

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved