A126376 Number of base 22 n-digit numbers with adjacent digits differing by one or less.

1, 22, 64, 188, 554, 1636, 4838, 14322, 42432, 125796, 373142, 1107334, 3287396, 9762746, 29001508, 86175356, 256122234, 761382468, 2263815846, 6732159798, 20023329732, 59563612974, 177208108824, 527277840216, 1569079157000

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1.

Links

Table of n, a(n) for n=0..24.

Formula

G.f.: (1+10*x-145*x^2+519*x^3-570*x^4-448*x^5+1162*x^6-155*x^7-584*x^8+130*x^9+76*x^10-7*x^11) / (1-12*x+55*x^2-111*x^3+54*x^4+140*x^5-182*x^6-15*x^7+96*x^8-14*x^9-12*x^10+x^11) (conjectured). - Colin Barker, Jul 18 2017

Prog

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

Crossrefs

Sequence in context: A081929 A305064 A124715 * A136604 A064710 A246415

Adjacent sequences: A126373 A126374 A126375 * A126377 A126378 A126379

Keyword

nonn,base

Author

R. H. Hardin, Dec 26 2006

Status

approved