A126523 Number of base 28 n-digit numbers with adjacent digits differing by four or less.

1, 28, 232, 1968, 16832, 144660, 1247088, 10773792, 93218308, 807453712, 6999891340, 60719731236, 526944732908, 4574529170580, 39722471511860, 344990169778032, 2996656884892004, 26032251950698948, 226161890813945336

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 28 differing by three or less A126496, two or less A126415, one or less A126382.

Sequence in context: A135180 A042524 A125365 * A115224 A135497 A138405

Adjacent sequences: A126520 A126521 A126522 * A126524 A126525 A126526

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved