100381

Appears in sequences

• Expansion of (1 +4*x -x^2)/((1-x^2)*(1-2*x-x^2)); a Pellian-related sequence.at n=12A114689
• Sequence a(n) = 3*A002559(n) - 2 determining the principal reduced indefinite binary quadratic form [1, a(n), -a(n)] for Markoff triples.at n=24A324250