login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A126494
Number of base 26 n-digit numbers with adjacent digits differing by three or less.
2
1, 26, 170, 1134, 7618, 51394, 347682, 2356702, 15997846, 108719102, 739490656, 5033426494, 34279838804, 233566488998, 1591993821168, 10854281793638, 74022763799812, 504910336091974, 3444546058508588, 23502038289723148
OFFSET
0,2
COMMENTS
[Empirical] a(base,n)=a(base-1,n)+7^(n-1) for base>=3n-2; a(base,n)=a(base-1,n)+7^(n-1)-2 when base=3n-3
PROG
(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>3)+($[i+1]`-$[i]`>3))
CROSSREFS
Cf. Base 26 differing by two or less A126413, one or less A126380.
Sequence in context: A268331 A125336 A321113 * A374489 A027001 A173893
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 27 2006
STATUS
approved