109522

Appears in sequences

• Number of (2+1)X(n+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally, diagonally or antidiagonally, with no adjacent elements equal.at n=10A232517
• a(n) is the least integer k such that n/(Sum_{j=1..n} 1/phi(k*j)) is an integer.at n=33A341813