129681

Appears in sequences

• Triangle of coefficients T(n,k) of y^k in Product_{k=0..n-1} (1 + (k+2)*y + y^2), read by rows of terms k = 0..2*n, for n >= 0.at n=55A324960
• Triangle of coefficients T(n,k) of y^k in Product_{k=0..n-1} (1 + (k+2)*y + y^2), read by rows of terms k = 0..2*n, for n >= 0.at n=57A324960
• a(n) is the coefficient of y^n in Product_{k=0..n} (1 + (k+2)*y + y^2), for n >= 0.at n=6A324962
• Odd numbers k, not powers of primes, such that sigma(k) == 2 modulo 8 and sigma(sigma(k)) == 6 modulo 8.at n=21A332458