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A126381
Number of base 27 n-digit numbers with adjacent digits differing by one or less.
4
1, 27, 79, 233, 689, 2041, 6053, 17967, 53367, 158601, 471557, 1402579, 4173131, 12419951, 36973123, 110090201, 327866769, 976616073, 2909516661, 8669262243, 25834637067, 76997534979, 229509874839, 684183138261, 2039795051133
OFFSET
0,2
COMMENTS
[Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>1)+($[i+1]`-$[i]`>1))
CROSSREFS
Sequence in context: A255186 A121737 A124726 * A129254 A215782 A216438
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 26 2006
STATUS
approved