A259410 a(n) = 1 - sigma(n) + sigma(n)^2 - sigma(n)^3 + sigma(n)^4.

1, 61, 205, 2101, 1111, 19141, 3641, 47461, 26521, 99451, 19141, 593461, 35855, 318505, 318505, 894661, 99451, 2255605, 152381, 3039331, 1016801, 1634221, 318505, 12747541, 894661, 3039331, 2497561, 9661961, 783871, 26505721, 1016801, 15506821, 5200081

Offset

1,2

Links

Robert Price, Table of n, a(n) for n = 1..10000

OEIS Wiki, Cyclotomic Polynomials at x=n, n! and sigma(n)

Formula

a(n) = 1 - A000203(n) + A000203(n)^2 - A000203(n)^3 + A000203(n)^4.

a(n) = A060884(A000203(n)). - Michel Marcus, Jun 26 2015

Mathematica

Table[1 - DivisorSigma[1, n] + DivisorSigma[1, n]^2 - DivisorSigma[1, n]^3 + DivisorSigma[1, n]^4, {n, 1, 10000}]
Table[Cyclotomic[10, DivisorSigma[1, n]], {n, 1, 10000}]

Prog

(PARI) a(n) = polcyclo(10, sigma(n)) \\ Michel Marcus, Jun 26 2015
(Magma) [(1 - DivisorSigma(1, n) + DivisorSigma(1, n)^2 - DivisorSigma(1, n)^3 + DivisorSigma(1, n)^4): n in [1..35]]; // Vincenzo Librandi, Jun 27 2015

Crossrefs

Cf. A000203 (sum of divisors of n).

Cf. A259411 (indices of primes in this sequence), A259412 (corresponding primes).

Sequence in context: A364716 A245865 A357780 * A234925 A171585 A038643

Adjacent sequences: A259407 A259408 A259409 * A259411 A259412 A259413

Keyword

easy,nonn

Author

Robert Price, Jun 26 2015

Status

approved