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A126523
Number of base 28 n-digit numbers with adjacent digits differing by four or less.
1
1, 28, 232, 1968, 16832, 144660, 1247088, 10773792, 93218308, 807453712, 6999891340, 60719731236, 526944732908, 4574529170580, 39722471511860, 344990169778032, 2996656884892004, 26032251950698948, 226161890813945336
OFFSET
0,2
COMMENTS
[Empirical] a(base,n)=a(base-1,n)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))
CROSSREFS
Cf. Base 28 differing by three or less A126496, two or less A126415, one or less A126382.
Sequence in context: A135180 A042524 A125365 * A115224 A135497 A138405
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 28 2006
STATUS
approved