19306983

Appears in sequences

• a(n) = 6*a(n-1) - a(n-2) - 2 with a(0) = 1, a(1) = 3.at n=10A011900
• Expansion of (1-3*x) / (1-5*x-5*x^2+x^3).at n=10A108475
• a(2n) = A011900(n), a(2n+1) = A001109(n+1).at n=20A113225
• Expansion of (1-x)/((1-x)^2 - x^2*(1+x)^2).at n=20A116404
• Numbers k such that k!/m! is a triangular number for some m < k-1.at n=16A227026