A138402 a(n) = (n-th prime)^4-(n-th prime)^2.

12, 72, 600, 2352, 14520, 28392, 83232, 129960, 279312, 706440, 922560, 1872792, 2824080, 3416952, 4877472, 7887672, 12113880, 13842120, 20146632, 25406640, 28392912, 38943840, 47451432, 62734320, 88519872, 104050200, 112540272

Offset: 1

Author

Artur Jasinski, Mar 19 2008

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200
• Index to sequences related to prime powers.

Crossrefs

Cf. A001248, A036689, A036690, A065471, A084920.

Programs

Magma

[NthPrime((n))^4 - NthPrime((n))^2: n in [1..30] ]; // Vincenzo Librandi, Jun 17 2011

Mathematica

a = {}; Do[p = Prime[n]; AppendTo[a, p^4 - p^2], {n, 1, 50}]; a
#^4-#^2&/@Prime[Range[30]] (* Harvey P. Dale, Sep 19 2018 *)

PARI

forprime(p=2,1e3,print1(p^4-p^2", ")) \\ Charles R Greathouse IV, Jun 16 2011

PARI

apply(p->p^4-p^2, primes(100)) \\ Charles R Greathouse IV, Apr 17 2015

Formula

Product_{n>=1} (1 - 1/a(n)) = A065471.

From Amiram Eldar, Nov 22 2022: (Start)

a(n) = A001248(n) * A084920(n).

a(n) = A036689(n) * A036690(n). (End)