A181091 - OEIS

%I #11 Sep 08 2022 08:45:54

%S 1,1,1,2,4,2,12,6,16,20,88,12,232,84,60,138,1596,144,1008,40,420,792,

%T 28656,264,3000,15080,5616,840,514228,60,335824,152214,19800,135660,

%U 141960,7632,13320,785232,135720,2160,1009256,420,433494436,94248

%N a(n) = Carmichael(F(n)), where F(n) are the Fibonacci numbers.

%C The Carmichael function is defined as the smallest integer m such that k^m == 1 (mod n) for all k relatively prime to n.

%H Vincenzo Librandi, <a href="/A181091/b181091.txt">Table of n, a(n) for n = 1..200</a>

%F a(n) = A002997(A000045(n)). - _Jonathan Vos Post_, Oct 02 2010

%e a(5) = 4 is in the sequence because Fibonacci(5) = 5, k^4 == 1 (mod 5) for k = 1,2,3,4;

%e a(7) = 12 is in the sequence because Fibonacci(7) = 13, k^12 == 1 (mod 7) for k = 1,2,3,4,5,6.

%t Table[Plus@@(Transpose[CarmichaelLambda[Fibonacci[n]]][[1]]), {n, 50}]

%o (Magma) [1,1] cat [CarmichaelLambda(Fibonacci(n)) : n in [3..60]]; // _Vincenzo Librandi_, Aug 15 2016

%Y Cf. A002997

%Y Cf. A000045. - _Jonathan Vos Post_, Oct 02 2010

%K nonn

%O 1,4

%A _Michel Lagneau_, Oct 02 2010