A126400 Number of base 13 n-digit numbers with adjacent digits differing by two or less.

1, 13, 59, 275, 1293, 6111, 28973, 137649, 654857, 3118273, 14857419, 70818391, 337647601, 1610116861, 7678944363, 36625115213, 174694226717, 833283367207, 3974811512311, 18960367898651, 90444302124667, 431438069091899

Offset

0,2

Comments

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

Links

Table of n, a(n) for n=0..21.

Formula

G.f.: (1+5*x-31*x^2-3*x^3+50*x^4-3*x^5-18*x^6) / ((1-x)*(1-7*x+7*x^2+19*x^3-6*x^4-9*x^5)) (conjectured). - Colin Barker, Jul 18 2017

Prog

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

Crossrefs

Cf. Base 13 differing by one or less A126367.

Sequence in context: A163833 A213567 A124864 * A297962 A354670 A220711

Adjacent sequences: A126397 A126398 A126399 * A126401 A126402 A126403

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved