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%I #16 Sep 08 2022 08:46:13
%S 2,82,257,2402,1297,20737,4097,50626,28562,104977,20737,614657,38417,
%T 331777,331777,923522,104977,2313442,160001,3111697,1048577,1679617,
%U 331777,12960001,923522,3111697,2560001,9834497,810001,26873857,1048577,15752962,5308417
%N a(n) = 1 + sigma(n)^4.
%H Robert Price, <a href="/A259308/b259308.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)^4.
%F a(n) = A019326(A000203(n)). - _Michel Marcus_, Jun 24 2015
%p with(numtheory): A259308:=n->1+sigma(n)^4: seq(A259308(n), n=1..50); # _Wesley Ivan Hurt_, Jul 09 2015
%t Table[1 + DivisorSigma[1, n]^4, {n, 10000}]
%t Table[Cyclotomic[8, DivisorSigma[1, n]], {n, 10000}]
%o (Magma) [(1 + SumOfDivisors(n)^4): n in [1..50]]; // _Vincenzo Librandi_, Jun 24 2015
%Y Cf. A000203 (sum of divisors of n).
%Y Cf. A259309 (indices of primes in this sequence), A259310 (corresponding primes).
%K easy,nonn
%O 1,1
%A _Robert Price_, Jun 24 2015
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