Number of permutations of {1,2,...,n} in which each element follows its proper divisors.
A016021
Number of permutations of {1,2,...,n} in which each element follows its proper divisors.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =12a(6) =25a(7) =150a(8) =378a(9) =1960a(10) =8154a(11) =81540a(12) =261250a(13) =3135000a(14) =19358040a(15) =160331626a(16) =719579700a(17) =11513275200a(18) =62702704800
External references
- oeis: A016021