1068096

Appears in sequences

• Number of (n+1)X8 0..1 arrays with the number of rightwards and downwards edge increases in each 2X2 subblock differing from the number in all its horizontal and vertical neighbors.at n=21A205071
• a(n) = floor(1/(1-s(n))) where s(n) = Sum_{k=1..n} phi(k)/k * log(2^k/(2^k-1)). phi(k) is the Euler totient function A000010(k).at n=18A383024