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%I #23 Sep 08 2022 08:46:13
%S 5,121,341,2801,1555,22621,4681,54241,30941,111151,22621,637421,41371,
%T 346201,346201,954305,111151,2374321,168421,3187591,1082401,1727605,
%U 346201,13179661,954305,3187591,2625641,10013305,837931,27252361,1082401,16007041,5421361
%N a(n) = 1 + sigma(n) + sigma(n)^2 + sigma(n)^3 + sigma(n)^4.
%H Robert Price, <a href="/A258978/b258978.txt">Table of n, a(n) for n = 1..10000</a>
%H 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 a(n) = 1 + A000203(n) + A000203(n)^2 + A000203(n)^3 + A000203(n)^4.
%F a(n) = A053699(A000203(n)). - _Michel Marcus_, Jun 25 2015
%p with(numtheory): A258978:=n->1+sigma(n)+sigma(n)^2+sigma(n)^3+sigma(n)^4: seq(A258978(n), n=1..40); # _Wesley Ivan Hurt_, Jul 09 2015
%t Table[1 + DivisorSigma[1, n] + DivisorSigma[1, n]^2 + DivisorSigma[1, n]^3 + DivisorSigma[1, n]^4, {n, 10000}]
%t Table[Cyclotomic[5, DivisorSigma[1, n]], {n, 10000}]
%t Total/@Table[DivisorSigma[1,n]^ex,{n,40},{ex,0,4}] (* _Harvey P. Dale_, Jun 24 2017 *)
%o (Magma) [(1 + DivisorSigma(1, n) + DivisorSigma(1, n)^2 + DivisorSigma(1, n)^3 + DivisorSigma(1, n)^4): n in [1..35]]; // _Vincenzo Librandi_, Jun 16 2015
%o (PARI) vector(50, n, polcyclo(6, sigma(n))) \\ _Michel Marcus_, Jun 25 2015
%Y Cf. A000203 (sum of divisors of n).
%Y Cf. A258979 (indices of primes in this sequence), A258980 (corresponding primes).
%K easy,nonn
%O 1,1
%A _Robert Price_, Jun 15 2015
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