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 A157430 Primes of the form 9*(p^4)-2 or 9*(p^4)+2, arising in Paley-Hadamard difference sets. 0
 727, 5623, 21611, 131771, 751691, 8311687, 16867447, 25431851, 71014331, 109056251, 350550731, 3170478247, 4435959611, 4678970407, 6353205851, 9659548091, 11977770247, 26525659687, 29365277771, 39262233611, 52986054967 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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. REFERENCES 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. LINKS EXAMPLE 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. CROSSREFS Sequence in context: A129117 A158394 A038600 * A215158 A178654 A094733 Adjacent sequences:  A157427 A157428 A157429 * A157431 A157432 A157433 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Mar 01 2009 EXTENSIONS More terms from R. J. Mathar, Mar 06 2009 STATUS approved

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Last modified April 6 11:51 EDT 2020. Contains 333273 sequences. (Running on oeis4.)