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 A089682 Primes of the form 3*m^2 - 1. 7
 2, 11, 47, 107, 191, 431, 587, 971, 1451, 2027, 2351, 2699, 3467, 4799, 5807, 6911, 7499, 8111, 8747, 10091, 10799, 14699, 15551, 16427, 17327, 18251, 25391, 27647, 36299, 41771, 44651, 55487, 57131, 62207, 67499, 71147, 74891, 80687, 92927 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 431 and 27647 also have the form 2*m^3-1 (431 = 3*12^2-1 = 2*6^3-1 and 27647 = 3*96^2-1 = 2*24^3-1). [Howard Berman (howard_berman(AT)hotmail.com), May 09 2009] Of course primes p such that 3*(p+1) is a square. [Vincenzo Librandi, Nov 18 2010] REFERENCES M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA Select[Table[3 n^2 - 1, {n, 0, 2000}], PrimeQ] (* Vincenzo Librandi, Jul 16 2012 *) PROG (MAGMA) [a: n in [0..200] | IsPrime(a) where a is 3*n^2-1]; // Vincenzo Librandi, Jul 16 2012 CROSSREFS Primes in A080663. Sequence in context: A229019 A142346 A106980 * A211671 A198693 A178710 Adjacent sequences:  A089679 A089680 A089681 * A089683 A089684 A089685 KEYWORD nonn,easy AUTHOR Giovanni Teofilatto, Jan 05 2004 EXTENSIONS More terms from Rick L. Shepherd, May 18 2005 STATUS approved

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Last modified April 19 06:30 EDT 2019. Contains 322237 sequences. (Running on oeis4.)