Numbers k such that sigma(k) is either their sibling in Doudna tree (A005940), or one of the sibling's descendants.
A347391
Numbers k such that sigma(k) is either their sibling in Doudna tree (A005940), or one of the sibling's descendants.
Terms
- a(0) =3a(1) =4a(2) =5a(3) =15a(4) =20a(5) =189a(6) =945a(7) =2125a(8) =6375a(9) =9261a(10) =46305a(11) =401625a(12) =19679625
External references
- oeis: A347391