16778058

Appears in sequences

• Number of permutations p of [n] whose absolute displacements |p(i)-i| are square numbers.at n=18A324375
• a(0) = 1; for n>0, a(n) is the smallest positive integer that has not previously occurred such that a(n-1)^2 + n^2 + a(n) is a square.at n=27A347595