A126385 Number of base 31 n-digit numbers with adjacent digits differing by one or less.

1, 31, 91, 269, 797, 2365, 7025, 20883, 62115, 184845, 550289, 1638775, 4881719, 14545715, 43350415, 129222077, 385262397, 1148802957, 3426077313, 10218944199, 30483682935, 90944672583, 271351287651, 809707376697

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

Links

Table of n, a(n) for n=0..23.

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: A360488 A139700 A124803 * A061155 A098440 A042892

Adjacent sequences: A126382 A126383 A126384 * A126386 A126387 A126388

Keyword

nonn,base

Author

R. H. Hardin, Dec 26 2006

Status

approved