1477440

Appears in sequences

• a(n) = sigma((4^n - 1)/3), where sigma(n) is the sum of positive divisors of n.at n=10A102359
• Number of nX3 arrays containing 3 copies of 0..n-1 with no element plus any vertical or antidiagonal neighbor equal to n-1.at n=4A266041
• T(n,k)=Number of nXk arrays containing k copies of 0..n-1 with no element plus any vertical or antidiagonal neighbor equal to n-1.at n=25A266042
• Number of 5Xn arrays containing n copies of 0..5-1 with no element plus any vertical or antidiagonal neighbor equal to 5-1.at n=2A266045
• Sum of the divisors of A001045(n) (Jacobsthal numbers).at n=21A366772