OFFSET
0,2
COMMENTS
a(n) = A054458(n+1,1) (second column of convolution triangle).
REFERENCES
R. P. Grimaldi, Ternary strings with no consecutive 0's and no consecutive 1's, Congressus Numerantium, 205 (2011), 129-149. (The sequence t_n, also the sequence lev_{n-1}.)
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,-2,-4,-1).
FORMULA
a(n) = ((4*n+3)*LP(n)+(2*n+1)*LP(n-1))/4, n >= 1, with LP(n) = A001333(n+1), a(0) = 1.
G.f.: ((1+x)/(1-2*x-x^2))^2.
MATHEMATICA
LinearRecurrence[{4, -2, -4, -1}, {1, 6, 23, 76}, 30] (* Paolo Xausa, Feb 06 2024 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Wolfdieter Lang, Apr 26 2000
STATUS
approved