565632

Appears in sequences

• Number of permutations of 1..n with displacements restricted to {-7,-6,-5,-4,-3,0,1,2}.at n=16A189602
• a(n) is the least number k such that the sequence of elements of the abundancy index of k is palindromic with length n, or -1 if no such k exists.at n=13A349689