A126513 - OEIS

A126513

Number of base 18 n-digit numbers with adjacent digits differing by four or less.

1, 18, 142, 1158, 9542, 79050, 656612, 5461074, 45448824, 378357098, 3150263772, 26231558496, 218432355062, 1818936380306, 15146831517282, 126132762778328, 1050352117472084, 8746662279539970, 72836658556602482

(list; graph; refs; listen; history; text; internal format)

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

LINKS

Table of n, a(n) for n=0..18.

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 18 differing by three or less A126486, two or less A126405, one or less A126372.

Sequence in context: A125355 A299834 A231951 * A232820 A143992 A127408

Adjacent sequences: A126510 A126511 A126512 * A126514 A126515 A126516

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved