A124715 Number of base 22 circular n-digit numbers with adjacent digits differing by 1 or less.

1, 22, 64, 148, 396, 1052, 2878, 7946, 22180, 62356, 176394, 501446, 1431426, 4100482, 11781736, 33940508, 97999060, 283533332, 821804362, 2385796886, 6936333286, 20192890166, 58855587316, 171732657416, 501596968522

Offset: 0

Author

R. H. Hardin, Dec 28 2006

Keywords

• nonn
• base

Comments

[Empirical] a(base,n)=a(base-1,n)+A002426(n+1) for base>=1.int(n/2)+1

a(n) = T(n, 22) where T(n, k) = Sum_{j=1..k} (1+2*cos(j*Pi/(k+1)))^n. These are the number of smooth cyclic words of length n over the alphabet {1,2,..,22}. See theorem 3.3 in Knopfmacher and others, reference in A124696. - Peter Luschny, Aug 13 2012

Links

• OEIS Wiki, Number of base k circular n-digit numbers with adjacent digits differing by d or less