-3992

Appears in sequences

• McKay-Thompson series of class 20d for Monster.at n=39A058559
• Triangle read by rows: n-th row (n>=0) gives coefficients of characteristic polynomial of n X n generalized Cartan matrix M defined in Comments.at n=60A136678
• Numerator of Hermite(n, 2/13).at n=3A159492
• a(1) = 1; a(n+1) = -Sum_{d|n} a(n/d) * a(d).at n=13A325303