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A125447
Number of base 12 circular n-digit numbers with adjacent digits differing by 8 or less.
0
1, 12, 132, 1380, 15260, 169252, 1879782, 20881502, 231972500, 2577002988, 28628206202, 318033966218, 3533075401202, 39249335918974, 436025331971998, 4843854954088810, 53810935050499732, 597791791563925916
OFFSET
0,2
COMMENTS
[Empirical] a(base,n)=a(base-1,n)+F(8) for base>=8.int(n/2)+1 and F(d) is the largest coefficient in (1+x+...+x^(2d))^n.
FORMULA
G.f.: (1-6*x^2-88*x^3+15*x^4+128*x^5-5*x^6-36*x^7) / ((1-2*x-x^2+x^3)*(1-10*x-13*x^2+7*x^3+6*x^4)) (conjectured). - Colin Barker, Jul 17 2017
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>8)+($[(i+1)mod N]`-$[i]`>8))
CROSSREFS
Sequence in context: A334334 A119237 A038729 * A162767 A003495 A324947
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 28 2006
STATUS
approved