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 A319183 a(n) = phi(n^n - 1)/n where phi is A000010. 1
 1, 4, 32, 280, 5040, 37856, 829440, 15676416, 589032000, 10374307328, 388566097920, 7619466454080, 390751784579520, 11138729990400000, 575561351791902720, 24328359845627701248, 1640651748984970444800, 34709116765970413844280, 2459108342476800000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS Main diagonal of the array T(n,k) = phi(n^k-1)/k for n > 1 and k > 1, which starts 1, 2, 2, 6, 6, 18, 16, ... A011260 2, 4, 8, 22, 48, 156, 320, ... A027385 4, 12, 32, 120, 288, 1512, 4096, ... A027695 4, 20, 48, 280, 720, 5580, 14976, ... A027741 12, 56, 216, 1240, 5040, 31992, 139968, ... A295496 8, 36, 160, 1120, 6048, 37856, 192000, ... A027743 18, 144, 432, 5400, 23328, 254016, 829440, ... A027744 LINKS Seiichi Manyama, Table of n, a(n) for n = 2..50 Eric W. Weisstein, MathWorld: Totient Function Wikipedia, Euler's totient function MATHEMATICA Table[EulerPhi[n^n-1]/n, {n, 20}] (* Harvey P. Dale, Aug 04 2020 *) PROG (PARI) {a(n) = eulerphi(n^n-1)/n} CROSSREFS Cf. A000010, A006486, A027385. Sequence in context: A246818 A145710 A264633 * A199566 A110901 A295538 Adjacent sequences: A319180 A319181 A319182 * A319184 A319185 A319186 KEYWORD nonn AUTHOR Seiichi Manyama, Sep 12 2018 STATUS approved

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Last modified December 6 08:36 EST 2022. Contains 358605 sequences. (Running on oeis4.)