271396

Appears in sequences

• Number of lower triangular n X n arrays colored with integers 0 upwards introduced in row major order, with no element equal to any horizontal, vertical, diagonal or antidiagonal neighbor, and containing the value n(n+1)/2-2.at n=37A211911
• E.g.f.: exp(sec(x)-1) = 1 + Sum_{n>0} a(n)*x^(2*n)/(2*n)!.at n=5A217502
• Integer averages of first n Fibonacci numbers (beginning with F(0)).at n=9A266960