login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A103776 Numbers n such that n and 8*n^2 + 4*n + 1 are primes. 2
2, 7, 11, 17, 41, 61, 101, 167, 227, 257, 281, 337, 347, 367, 397, 401, 461, 467, 487, 541, 571, 587, 601, 631, 641, 647, 661, 691, 701, 761, 857, 947, 971, 977, 997, 1021, 1087, 1237, 1277, 1291, 1381, 1451, 1481, 1607, 1621, 1627, 1667, 1697, 1787, 1811 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Prime[Range[300]], PrimeQ[8 #^2 + 4 # + 1]&] (* Harvey P. Dale, Jan 04 2011 *)

PROG

(MAGMA) [n: n in [0..2000] | IsPrime(n) and IsPrime(8*n^2 + 4*n + 1)]; // Vincenzo Librandi, Feb 03 2014

CROSSREFS

Cf. A102083.

Sequence in context: A109417 A045372 A273600 * A260889 A289994 A040154

Adjacent sequences:  A103773 A103774 A103775 * A103777 A103778 A103779

KEYWORD

nonn,easy

AUTHOR

Zak Seidov, Feb 15 2005

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 14:30 EDT 2020. Contains 333107 sequences. (Running on oeis4.)