

A090697


Numbers n such that n^2/2  1 is a prime.


5



4, 6, 8, 12, 14, 16, 20, 22, 26, 30, 34, 36, 42, 44, 48, 50, 56, 68, 72, 76, 78, 82, 84, 86, 90, 92, 98, 100, 104, 112, 118, 124, 126, 128, 138, 146, 152, 160, 162, 170, 174, 182, 184, 190, 196, 204, 216, 218, 224, 226, 230, 236, 250, 252, 254, 264, 268, 274, 280
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OFFSET

1,1


COMMENTS

A066436 gives resulting primes p such that 2p+2 is square.  Chandler


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

Harvey P. Dale, Table of n, a(n) for n = 1..1000


FORMULA

a(n) = 2*A066049(n) = A110558(n)/2.  Chandler


MATHEMATICA

Select[Range[2, 300, 2], PrimeQ[#^2/21]&] (* Harvey P. Dale, Apr 05 2014 *)


CROSSREFS

Cf. A066049, A066436, A091176, A110558.
Sequence in context: A117247 A249722 A047407 * A225508 A235036 A107303
Adjacent sequences: A090694 A090695 A090696 * A090698 A090699 A090700


KEYWORD

easy,nonn


AUTHOR

Giovanni Teofilatto, Dec 20 2003


EXTENSIONS

Corrected and extended by Ray Chandler, Dec 25 2003


STATUS

approved



