A087026 Euler's totient of n-th cyclic number.

77760, 1382399778816000, 98221093640386560, 1053590173895849103360, 821095240766161265049600000, 511883170649353472639948811682935064652736000, 410719109641406326635474611575828305116907342385175347200

Offset

1,1

Comments

Calculated with Dario Alpern's ECM.

Extended using factors of 10^(A001913(n)-1)-1, see Kamada link.

Links

Max Alekseyev, Table of n, a(n) for n = 1..51 (first 42 terms from Ray Chandler)

Dario A. Alpern, Factorization using the Elliptic Curve Method.

Makoto Kamada, Factorizations of 11...11 (Repunit)

Eric Weisstein's World of Mathematics, Cyclic Number.

Eric Weisstein's World of Mathematics, Totient Function.

Formula

a(n) = A000010(A004042(n+1)).

Crossrefs

Cf. A001913, A087020, A087021, A087022, A087023, A087024, A087025.

Sequence in context: A069044 A250012 A235979 * A133971 A133973 A133974

Adjacent sequences: A087023 A087024 A087025 * A087027 A087028 A087029

Keyword

nonn

Author

Reinhard Zumkeller, Jul 30 2003

Extensions

a(12)-a(42) from Ray Chandler, Nov 16 2011

Status

approved