A138426 a(n) = ((prime(n))^5-prime(n))/5.

6, 48, 624, 3360, 32208, 74256, 283968, 495216, 1287264, 4102224, 5725824, 13868784, 23171232, 29401680, 45868992, 83639088, 142984848, 168919248, 270025008, 360845856, 414614304, 615411264, 787808112, 1116811872

Offset: 1

Author

Artur Jasinski, Mar 19 2008

Keywords

• nonn
• easy

Comments

Number of monic irreducible polynomials of degree 5 over GF(prime(n)). - Robert Israel, Jan 07 2015

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200
• Wikipedia, Necklace polynomial

Crossrefs

Cf. A008837, A127919, A138420, A208536.

Programs

Magma

[(NthPrime((n))^5 - NthPrime((n)))/5: n in [1..30] ]; // Vincenzo Librandi, Jun 18 2011

Maple

seq((ithprime(i)^5-ithprime(i))/5, i = 1 .. 50); # Robert Israel, Jan 07 2015

Mathematica

a = {}; Do[p = Prime[n]; AppendTo[a, (p^5 - p)/5], {n, 1, 50}]; a
(#^5-#)/5&/@Prime[Range[30]] (* Harvey P. Dale, Mar 12 2018 *)

PARI

forprime(p=2,1e3,print1((p^5-p)/5", ")) \\ Charles R Greathouse IV, Jul 15 2011

Formula

a(n) = A138404(n)/5. - R. J. Mathar, Oct 15 2017