A259371 Primes of the form 1 + sigma(n)^3 + sigma(n)^6.

3, 757, 262657, 64008001, 46656216001, 30841155073, 729027001, 46656216001, 30841155073, 225200075257, 885843322057, 46656216001, 41407378175593, 885843322057, 25002115044733, 1126163480473, 85766130261001, 191102989824001, 85766130261001, 41407378175593

Offset

1,1

Comments

These primes are neither sorted nor uniqued. They are listed in the order found in A259369.

Links

Robert Price, Table of n, a(n) for n = 1..756

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

Formula

a(n) = A259369(A259370(n)).

Maple

with(numtheory): b:=n->1+sigma(n)^3+sigma(n)^6: A259371:=n->`if`( isprime(b(n)), b(n), NULL): seq(A259371(n), n=1..200); # Wesley Ivan Hurt, Jun 29 2015

Mathematica

Select[Table[1 + DivisorSigma[1, n]^3 + DivisorSigma[1, n]^6, {n, 10000}], PrimeQ]
Select[Table[Cyclotomic[9, DivisorSigma[1, n]], {n, 10000}], PrimeQ]

Prog

(Magma) [a: n in [1..150] | IsPrime(a) where a is 1 + SumOfDivisors(n)^3 + SumOfDivisors(n)^6]; // Vincenzo Librandi, Jun 26 2015

Crossrefs

Cf. A000203, A259369, A259370.

Sequence in context: A307926 A172895 A259369 * A294794 A293252 A341567

Adjacent sequences: A259368 A259369 A259370 * A259372 A259373 A259374

Keyword

easy,nonn

Author

Robert Price, Jun 25 2015

Status

approved