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A188574 Numbers n such that n^2 + 2*n + 2^n is prime. 0
1, 3, 5, 7, 13, 15, 35, 43, 159, 245, 265, 1573, 1827, 3359, 3949, 4615, 5463, 5919, 19723 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..19.

MATHEMATICA

Select[Range[1, 10000, 2], PrimeQ[#^2 + 2 # + 2^#] &]

PROG

(PARI) is(n)=ispseudoprime(n^2+2*n+2^n) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A220425 (see the comment by Jonathan Vos Post).

Sequence in context: A157834 A192110 A246026 * A247458 A008996 A261089

Adjacent sequences:  A188571 A188572 A188573 * A188575 A188576 A188577

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Jan 07 2013

EXTENSIONS

a(19) from Bruno Berselli, Jan 09 2013

STATUS

approved

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Last modified February 22 23:44 EST 2020. Contains 332157 sequences. (Running on oeis4.)