A126542 Number of base 21 n-digit numbers with adjacent digits differing by five or less.

1, 21, 201, 1991, 19931, 200563, 2023003, 20427271, 206365349, 2085257937, 21073012213, 212967505695, 2152331164583, 21752488014247, 219841986401257, 2221842059480575, 22455157743187179, 226944263887382495

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+11^(n-1) for base>=5n-4; a(base,n)=a(base-1,n)+11^(n-1)-2 when base=5n-5

Links

Table of n, a(n) for n=0..17.

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>5)+($[i+1]`-$[i]`>5))

Crossrefs

Cf. Base 21 differing by four or less A126516, three or less A126489, two or less A126408, one or less A126375.

Sequence in context: A337897 A341399 A125384 * A297906 A298500 A298319

Adjacent sequences: A126539 A126540 A126541 * A126543 A126544 A126545

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved