99658

Appears in sequences

• a(n) = A047098(n)/2.at n=7A047099
• Expansion of f(x^3)/(1-x*f(x^3)), where f(x) is the g.f. of A001764, whose n-th term is binomial(3n,n)/(2n+1).at n=23A126042
• Sequence h_n arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition).at n=15A129874
• Number A(n,k) of 3n-length k-ary words, either empty or beginning with the first letter of the alphabet, that can be built by repeatedly inserting triples of identical letters into the initially empty word; square array A(n,k), n>=0, k>=0, by antidiagonals.at n=63A213027