71418

Appears in sequences

• Planar trees where no branch is identical to its adjacent neighbor.at n=16A106363
• Number of nX4 0..1 arrays with every element equal to 0, 1, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=16A302511
• a(n) = Sum_{k=1..n} sigma(k)*sigma(2*k), where sigma(n) = A000203(n) is the sum of the divisors of n.at n=30A347108