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A284089
Smallest number k such that gcd(phi(k), k-1) = n * lambda(k).
3
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
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
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