Composite numbers k such that A347381 obtains the same value for all divisors of k that are larger than one, where A347381 is the distance from n to the nearest common ancestor of n and sigma(n) in the Doudna-tree (A005940).
A374219
Composite numbers k such that A347381 obtains the same value for all divisors of k that are larger than one, where A347381 is the distance from n to the nearest common ancestor of n and sigma(n) in the Doudna-tree (A005940).
Terms
- a(0) =15a(1) =77a(2) =1403a(3) =3127a(4) =3139a(5) =8383a(6) =15247a(7) =45151a(8) =47263a(9) =54053a(10) =58339a(11) =65473a(12) =73813a(13) =79567a(14) =89951a(15) =94957a(16) =155011a(17) =211621a(18) =293323a(19) =333961a(20) =360883a(21) =441901a(22) =444853a(23) =496597a(24) =612893a(25) =623659a(26) =646367a(27) =727393a(28) =786193a(29) =796723
External references
- oeis: A374219