A126494 Number of base 26 n-digit numbers with adjacent digits differing by three or less.

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

Links

Table of n, a(n) for n=0..19.

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

Adjacent sequences: A126491 A126492 A126493 * A126495 A126496 A126497

Keyword

nonn,base

Author

R. H. Hardin, Dec 27 2006

Status

approved