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A126538
Number of base 17 n-digit numbers with adjacent digits differing by five or less.
0
1, 17, 157, 1507, 14607, 142041, 1382455, 13458785, 131037075, 1275829041, 12422061043, 120947162241, 1177600426155, 11465692698745, 111635587544291, 1086938653558289, 10582966126771531, 103040932264504713
OFFSET
0,2
COMMENTS
[Empirical] a(base,n)=a(base-1,n)+11^(n-1) for base>=5n-4; a(base,n)=a(base-1,n)+11^(n-1)-2 when base=5n-5.
FORMULA
G.f.: (1+6*x-24*x^2-54*x^3+42*x^4+72*x^5-16*x^6-24*x^7) / (1-11*x+6*x^2+64*x^3-18*x^4-76*x^5+8*x^6+24*x^7) (conjectured). - Colin Barker, Jul 18 2017
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>5)+($[i+1]`-$[i]`>5))
CROSSREFS
Cf. Base 17 differing by four or less A126512, three or less A126485, two or less A126404, one or less A126371.
Sequence in context: A176838 A176622 A125380 * A164746 A198859 A160295
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 28 2006
STATUS
approved