login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157430 Primes of the form 9*(p^4)-2 or 9*(p^4)+2, arising in Paley-Hadamard difference sets. 0

%I #3 Mar 30 2012 18:40:49

%S 727,5623,21611,131771,751691,8311687,16867447,25431851,71014331,

%T 109056251,350550731,3170478247,4435959611,4678970407,6353205851,

%U 9659548091,11977770247,26525659687,29365277771,39262233611,52986054967

%N Primes of the form 9*(p^4)-2 or 9*(p^4)+2, arising in Paley-Hadamard difference sets.

%C Polhill is able to construct Paley-Hadamard difference sets of the Stanton-Sprott family in groups of the form (Z_3)^2 X (Z_p)^4t X (Z_(9p^4t)+2 or -2 when 9*(p^4t)-2 or 9*(p^4t)+2 is a prime power. In this sequence, we are taking just the t=1 case, a prime power as first power of prime.

%D John Bowen Polhill, Paley partial difference sets in groups with order not a prime power, 1046th Meeting of the AMS, Washington, DC, January 5-8, 2009.

%e a(1) = 9*(3^4) - 2 = 727 is prime. a(2) = 9*(5^4) - 2 = 5623 is prime. a(3) = 9*(7^4) + 2 = 21611. a(4) = 9*(11^4) + 2 = 131771. a(5) = 9*(17^4) + 2 = 751691. a(6) = 9*(31^4) - 2 = 8311687. a(7) = 9*(37^4) - 2 = 16867447. a(8) = 9*(41^4) + 2 = 25431851.

%K easy,nonn

%O 1,1

%A _Jonathan Vos Post_, Mar 01 2009

%E More terms from _R. J. Mathar_, Mar 06 2009

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 23 16:40 EDT 2024. Contains 371916 sequences. (Running on oeis4.)