A087025 Sum of divisors of n-th cyclic number.

255360, 17205180696931968, 1951532915603927040, 12430490030984319840000, 9956179688423375044684800000, 6080633705911286890368486450696472902951229440, 4809378729404888733987843426081300724182624228548100710400

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, Divisor Function

Formula

a(n) = A000203(A004042(n+1)).

Crossrefs

Cf. A001913, A087020, A087021, A087022, A087023, A087024, A087026.

Sequence in context: A034631 A168352 A147579 * A249915 A161534 A052197

Adjacent sequences: A087022 A087023 A087024 * A087026 A087027 A087028

Keyword

nonn

Author

Reinhard Zumkeller, Jul 30 2003

Extensions

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

Status

approved