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

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

Offset: 1

Author

Reinhard Zumkeller, Jul 30 2003

Keywords

• nonn

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.

Crossrefs

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

Formula

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

Extensions

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