Number of permutations of {1..n} with three consecutive terms in arithmetic progression.
A333631
Number of permutations of {1..n} with three consecutive terms in arithmetic progression.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =2a(4) =6a(5) =40a(6) =238a(7) =1760a(8) =14076a(9) =131732a(10) =1308670a(11) =14678452a(12) =176166906a(13) =2317481348a(14) =32416648496a(15) =490915956484
External references
- oeis: A333631