A126520 Number of base 25 n-digit numbers with adjacent digits differing by four or less.

1, 25, 205, 1725, 14645, 124977, 1069941, 9179469, 78869491, 678323799, 5838030793, 50269401543, 432996699399, 3730477803939, 32144938184273, 277017865876053, 2387456054541987, 20577155216208681, 177357954676723141

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 25 differing by three or less A126493, two or less A126412, one or less A126379.

Sequence in context: A042210 A220677 A125362 * A324794 A348201 A264493

Adjacent sequences: A126517 A126518 A126519 * A126521 A126522 A126523

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved