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A174142 Either 2*n^2-+3 is a prime. 1
0, 1, 4, 7, 8, 10, 11, 14, 16, 19, 20, 22, 23, 28, 34, 35, 37, 40, 41, 43, 46, 47, 49, 50, 56, 59, 62, 65, 70, 71, 74, 76, 79, 82, 83, 85, 92, 94, 95, 98, 100, 101, 103, 106, 107, 113, 118, 119, 127, 128, 130, 131, 133, 139, 151, 161, 166, 169, 170, 175, 176, 181, 184 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

A010051(2*a(n)^2 - 3) + A010051(2*a(n)^2 + 3) = 1. [From Reinhard Zumkeller, Mar 31 2010]

LINKS

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

EXAMPLE

a(1)=0 because 2*0^2-3=-3=nonprime and 2*0^2+3=3=prime; a(2)=1 because 2*1^2-3=-1=nonprime and 2*1^2+3=5=prime; a(3)=4 because 2*4^2-3=29=prime and 2*4^2+3=35=nonprime; a(4)=7 because 2*7^2-3=95=nonprime and 2*7^2+3=101=prime.

MATHEMATICA

Join[{0}, Select[Range[200], Sort[PrimeQ[2 #^2+{3, -3}]]=={False, True}&]] (* Harvey P. Dale, Apr 06 2012 *)

CROSSREFS

Cf. A001105.

Sequence in context: A214206 A026316 A283767 * A091158 A175553 A284684

Adjacent sequences:  A174139 A174140 A174141 * A174143 A174144 A174145

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Mar 09 2010

EXTENSIONS

Extended beyond 71 by R. J. Mathar, Apr 20 2010

STATUS

approved

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Last modified March 29 15:16 EDT 2020. Contains 333107 sequences. (Running on oeis4.)