A125371 Number of base 8 circular n-digit numbers with adjacent digits differing by 5 or less.

1, 8, 58, 398, 2902, 21238, 155716, 1142016, 8376142, 61435910, 450611298, 3305081546, 24241659940, 177804417188, 1304135570978, 9565395603838, 70158958263262, 514592352357838, 3774361758858916, 27683673535999896

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+F(5) for base>=5.int(n/2)+1 and F(d) is the largest coefficient in (1+x+...+x^(2d))^n.

Links

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

Formula

G.f.: (1 - 3*x^2 - 28*x^3 + 3*x^4 + 16*x^5) / ((1 - x - x^2)*(1 - 7*x - 3*x^2 + 4*x^3)) (conjectured). - Colin Barker, Jun 03 2017

Prog

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

Crossrefs

Sequence in context: A055839 A297097 A081897 * A162272 A273584 A037532

Adjacent sequences: A125368 A125369 A125370 * A125372 A125373 A125374

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved