login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A089238 Numbers n such that 3*n^2/2 - 1 is a prime. 0
2, 4, 6, 10, 14, 16, 20, 24, 26, 34, 40, 44, 54, 56, 60, 64, 70, 76, 86, 90, 104, 110, 116, 120, 124, 126, 130, 136, 140, 146, 150, 154, 164, 166, 174, 186, 194, 200, 204, 230, 240, 244, 260, 264, 286, 300, 306, 336, 346, 354, 374, 386, 394, 400, 414, 416, 420 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms must be even numbers. - Harvey P. Dale, Jul 03 2017

REFERENCES

M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988

Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997

LINKS

Table of n, a(n) for n=1..57.

MATHEMATICA

Select[Range[0, 500, 2], PrimeQ[(3#^2)/2-1]&] (* Harvey P. Dale, Jul 03 2017 *)

PROG

(PARI) forstep(n=2, 1000, 2, if(isprime(3*n^2/2-1), print1(n, ", "))) - Rick L. Shepherd, May 06 2008

CROSSREFS

Cf. A090686.

Sequence in context: A075574 A104692 A066755 * A005574 A109807 A259645

Adjacent sequences:  A089235 A089236 A089237 * A089239 A089240 A089241

KEYWORD

nonn

AUTHOR

Giovanni Teofilatto, Dec 22 2003

EXTENSIONS

Corrected and extended by Rick L. Shepherd, May 06 2008

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified January 22 08:47 EST 2018. Contains 298042 sequences.