131920

Appears in sequences

• Define f(n) by e(n+1) = e(n) + 3^{n+1} - 1 + 2*f(n), where the rational numbers e(n) are defined in A134939; then a(n) is the numerator of f(n).at n=4A134940
• Number of nX1 0..3 arrays with all rows and columns having a nonnegative second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative.at n=8A223403
• Expansion of e.g.f. Product_{i>=1, j>=1} (1 + x^(i*j)/(i*j)).at n=8A318694