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.
FORMULA
G.f.: (1+7*x-57*x^2+73*x^3+75*x^4-121*x^5-33*x^6+37*x^7+4*x^8) / (1-8*x+20*x^2-8*x^3-30*x^4+24*x^5+12*x^6-8*x^7-x^8) (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
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 26 2006
STATUS
approved