A284089 Smallest number k such that gcd(phi(k), k-1) = n * lambda(k).

1, 2465, 314821, 15841, 658801, 41041, 21584305, 8830801, 8911, 11205601, 3193414093, 1729, 9653421961, 1193229577, 1232469001, 69331969, 1419339691, 46657, 587034735001, 9439201, 64774081, 67047668161, 100929219805, 7995169, 1894344001, 212027401, 67371265, 3057601

Offset

1,2

Comments

For n > 1, a(n) is a Carmichael number.

a(19) <= 587034735001. - Giovanni Resta, Mar 24 2017

Links

Amiram Eldar, Table of n, a(n) for n = 1..138

Mathematica

m=10; s=Table[0, {m}]; c=0; k=0; While[c<m, k++; If[IntegerQ[n = GCD[EulerPhi[k], k-1]/CarmichaelLambda[k]] && n<=m && s[[n]] == 0, c++; s[[n]]=k]]; s (* Amiram Eldar, Jun 26 2019 *)

Crossrefs

Cf. A000010, A002322, A002997, A049559, A264024.

Sequence in context: A365022 A329240 A182381 * A252113 A102689 A082253

Adjacent sequences: A284086 A284087 A284088 * A284090 A284091 A284092

Keyword

nonn

Author

Altug Alkan and Thomas Ordowski, Mar 24 2017

Extensions

a(7)-a(18) from Giovanni Resta, Mar 24 2017

a(19)-a(28) from Amiram Eldar, Jun 26 2019

Status

approved