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A125408
Number of base 20 circular n-digit numbers with adjacent digits differing by 6 or less.
0
1, 20, 218, 1994, 21078, 227450, 2509508, 28044008, 316237326, 3587876114, 40876370578, 467018577782, 5345948876388, 61273602792708, 702905295827666, 8068104827974874, 92643421204990558, 1064070251138125106
OFFSET
0,2
COMMENTS
[Empirical] a(base,n)=a(base-1,n)+F(6) for base>=6.int(n/2)+1 and F(d) is the largest coefficient in (1+x+...+x^(2d))^n
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>6)+($[(i+1)mod N]`-$[i]`>6))
CROSSREFS
Sequence in context: A128823 A141790 A229575 * A213351 A140236 A341371
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 28 2006
STATUS
approved