login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A138420 a(n) = ((prime(n))^4-(prime(n))^2)/4. 5
3, 18, 150, 588, 3630, 7098, 20808, 32490, 69828, 176610, 230640, 468198, 706020, 854238, 1219368, 1971918, 3028470, 3460530, 5036658, 6351660, 7098228, 9735960, 11862858, 15683580, 22129968, 26012550, 28135068, 32767038, 35286570 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Number of monic irreducible polynomials of degree 4 over GF(prime(n)). - Robert Israel, Jan 07 2015

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..200

FORMULA

a(n) = A138402(n)/4. - R. J. Mathar, Oct 15 2017

MAPLE

seq(1/4*(ithprime(i)^4 - ithprime(i)^2), i=1..100); # Robert Israel, Jan 07 2015

MATHEMATICA

a = {}; Do[p = Prime[n]; AppendTo[a, (p^4 - p^2)/4], {n, 1, 50}]; a

PROG

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

(PARI) forprime(p=2, 1e3, print1((p^4-p^2)/4", ")) \\ Charles R Greathouse IV, Jul 15 2011

CROSSREFS

Cf. A008837, A127919, A138420, A138426.

Sequence in context: A118331 A240921 A221961 * A152409 A200320 A347020

Adjacent sequences:  A138417 A138418 A138419 * A138421 A138422 A138423

KEYWORD

nonn,easy

AUTHOR

Artur Jasinski, Mar 19 2008

EXTENSIONS

Name edited by Robert Israel, Jan 07 2015

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 27 03:09 EST 2022. Contains 350601 sequences. (Running on oeis4.)