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A124843
Number of base 8 circular n-digit numbers with adjacent digits differing by 2 or less.
2
1, 8, 34, 122, 502, 2098, 8980, 38928, 170382, 750722, 3323554, 14763438, 65736004, 293186252, 1309156946, 5850527002, 26160514526, 117022825786, 523619082772, 2343388805944, 10488943094022, 46952619517170
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; also confirms conjectured g.f. from Colin Barker. - Ray Chandler, Aug 12 2023.
FORMULA
G.f.: (1 - 15*x^2 - 20*x^3 + 87*x^4 + 16*x^5 - 60*x^6) / ((1 - 3*x - x^2 + 2*x^3)*(1 - 5*x + x^2 + 6*x^3)). - Colin Barker, Jun 03 2017
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>2)+($[(i+1)mod N]`-$[i]`>2))
CROSSREFS
Cf. Row 8 of A285280.
Sequence in context: A196334 A294844 A302083 * A082840 A224240 A101644
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 28 2006
STATUS
approved