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A126376
Number of base 22 n-digit numbers with adjacent digits differing by one or less.
4
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.
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
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 26 2006
STATUS
approved