A126411 Number of base 24 n-digit numbers with adjacent digits differing by two or less.

1, 24, 114, 550, 2668, 12986, 63348, 309524, 1514230, 7415030, 36339360, 178207260, 874402930, 4292397700, 21079558088, 103555346934, 508877542076, 2501307731338, 12297585994658, 60472695897300, 297423291148782

Offset: 0

Author

R. H. Hardin, Dec 28 2006

Keywords

• nonn
• base

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

• Alois P. Heinz, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. Base 24 differing by one or less A126378.

Programs

Maple

b:= proc(n, i) option remember; `if`(n=0, 1, add(
     `if`(i=0 or abs(i-j)<3, b(n-1, j), 0), j=1..24))
    end:
a:= n-> b(n, 0):
seq(a(n), n=0..20);  # Alois P. Heinz, Sep 25 2015

Formula

G.f.: -(8*x^12 +49*x^11 -117*x^10 -525*x^9 +450*x^8 +1346*x^7 -678*x^6 -1203*x^5 +458*x^4 +302*x^3 -145*x^2 +11*x +1) / (2*x^12 +11*x^11 -33*x^10 -115*x^9 +150*x^8 +286*x^7 -260*x^6 -237*x^5 +190*x^4 +38*x^3 -53*x^2 +13*x -1). - Alois P. Heinz, Sep 25 2015