A126376 - OEIS

%I #9 Jul 19 2017 07:34:29

%S 1,22,64,188,554,1636,4838,14322,42432,125796,373142,1107334,3287396,

%T 9762746,29001508,86175356,256122234,761382468,2263815846,6732159798,

%U 20023329732,59563612974,177208108824,527277840216,1569079157000

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

%C [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.

%F 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

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

%K nonn,base

%O 0,2

%A _R. H. Hardin_, Dec 26 2006