43540

Appears in sequences

• a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = (F(2), F(3), ...).at n=17A024591
• a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = (F(2), F(3), F(4), ...).at n=16A025105
• Numbers k such that 2^(2*k+1) + 2^k + 1 is prime.at n=43A105180
• Icosagonal numbers divisible by 20.at n=14A117798
• Permutation trees of power n and height k.at n=41A179454
• Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 10, and no two adjacent values equal.at n=6A233684
• Number of (n+1)X(7+1) 0..3 arrays with every 2X2 subblock having the sum of the squares of the edge differences equal to 10, and no two adjacent values equal.at n=0A233690
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with every 2X2 subblock having the sum of the squares of the edge differences equal to 10 (10 maximizes T(1,1)), and no two adjacent values equal.at n=21A233691
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with every 2X2 subblock having the sum of the squares of the edge differences equal to 10 (10 maximizes T(1,1)), and no two adjacent values equal.at n=27A233691
• Magic sums of 4 X 4 magic squares composed of odd squares.at n=19A271582
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 673", based on the 5-celled von Neumann neighborhood.at n=31A273406
• a(n) is the number of edges formed by n-secting the angles of a decagon.at n=33A335802
• Number of edges among all distinct circles that can be constructed from a 2 X n square grid of points using only a compass.at n=8A359861