This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A259410 #13 Sep 08 2022 08:46:13
%S A259410 1,61,205,2101,1111,19141,3641,47461,26521,99451,19141,593461,35855,
%T A259410 318505,318505,894661,99451,2255605,152381,3039331,1016801,1634221,
%U A259410 318505,12747541,894661,3039331,2497561,9661961,783871,26505721,1016801,15506821,5200081
%N A259410 a(n) = 1 - sigma(n) + sigma(n)^2 - sigma(n)^3 + sigma(n)^4.
%H A259410 Robert Price, <a href="/A259410/b259410.txt">Table of n, a(n) for n = 1..10000</a>
%H A259410 OEIS Wiki, <a href="https://oeis.org/wiki/Cyclotomic Polynomials at x=n, n! and sigma(n)">Cyclotomic Polynomials at x=n, n! and sigma(n)</a>
%F A259410 a(n) = 1 - A000203(n) + A000203(n)^2 - A000203(n)^3 + A000203(n)^4.
%F A259410 a(n) = A060884(A000203(n)). - _Michel Marcus_, Jun 26 2015
%t A259410 Table[1 - DivisorSigma[1, n] + DivisorSigma[1, n]^2 - DivisorSigma[1, n]^3 + DivisorSigma[1, n]^4, {n, 1, 10000}]
%t A259410 Table[Cyclotomic[10, DivisorSigma[1, n]], {n, 1, 10000}]
%o A259410 (PARI) a(n) = polcyclo(10, sigma(n)) \\ _Michel Marcus_, Jun 26 2015
%o A259410 (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
%Y A259410 Cf. A000203 (sum of divisors of n).
%Y A259410 Cf. A259411 (indices of primes in this sequence), A259412 (corresponding primes).
%K A259410 easy,nonn
%O A259410 1,2
%A A259410 _Robert Price_, Jun 26 2015