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A206328 Primes of the form n^2+1 such that (n+2)^2+1 is also prime. 3
5, 17, 197, 577, 2917, 15377, 41617, 147457, 215297, 401957, 414737, 509797, 1196837, 1308737, 1378277, 1547537, 1623077, 1726597, 1887877, 2446097, 2604997, 2802277, 2835857, 3857297, 4218917, 4343057, 4384837, 5779217, 6022117, 6421157, 7096897, 8031557 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes corresponding to A096012 and subset of A002496.

For n > 1, a(n) ==7 (mod 10) because n ==4 (mod 10).

Conjecture: this sequence is infinite.

LINKS

Table of n, a(n) for n=1..32.

EXAMPLE

For n = 4, n^2 + 1 = 17 is prime and  (n+2)^2 + 1 = 37 is also prime => 17 is in the sequence.

MAPLE

for n from 1 to 4000 do: x:=n^2+1:y:=(n+2)^2+1:if type(x, prime)=true and type(y, prime)=true then printf(`%d, `, x): else fi:od:

CROSSREFS

Cf. A096012, A002496.

Sequence in context: A164740 A053678 A090645 * A096407 A216428 A062230

Adjacent sequences:  A206325 A206326 A206327 * A206329 A206330 A206331

KEYWORD

nonn,easy

AUTHOR

Michel Lagneau, Feb 06 2012

STATUS

approved

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Last modified July 11 17:18 EDT 2020. Contains 335626 sequences. (Running on oeis4.)