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 A110284 Squares of the form 4p - 3, where p is a prime. 8
 9, 25, 49, 121, 169, 289, 625, 841, 961, 1225, 1681, 1849, 2401, 3025, 4489, 5929, 6889, 10201, 11881, 13225, 14161, 15625, 17689, 19321, 20449, 22801, 24025, 24649, 25921, 32041, 32761, 39601, 41209, 44521, 48841, 49729, 55225, 57121, 69169 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also: squares of the form 2*s-3, where s is a semiprime, A107317. - Franklin T. Adams-Watters, Jun 28 2010 Squares are less dense then primes and easy to generate so it's faster to check squares if they are of the required form than to check if primes are of the required form. - David A. Corneth, Oct 15 2018 LINKS David A. Corneth, Table of n, a(n) for n = 1..16289 (First 1316 terms by Marius A. Burtea, terms < 10^11) FORMULA a(n) = 4*A002383(n) - 3 = A088503(n-1)^2. MATHEMATICA Select[ 4Prime[ Range[2000]] - 3, IntegerQ[ Sqrt[ # ]] &] (* Robert G. Wilson v, Sep 20 2005 *) PROG (PARI) isok(n) = issquare(n) && (p=(n+3)/4) && (frac(p)==0) && isprime(p); \\ Michel Marcus, Oct 15 2018 (PARI) upto(n) = my(res = List()); forstep(i = 3, sqrtint(n), 2, if(isprime((i^2+3)/4), listput(res, i^2))); res \\ David A. Corneth, Oct 15 2018 (MAGMA) [4*p - 3: p in PrimesUpTo(10^5)|IsSquare (4*p - 3)]; // Vincenzo Librandi, Oct 17 2018 CROSSREFS Cf. A002383, A002384, A088503, A001358. Sequence in context: A141768 A339126 A176970 * A109367 A110588 A282631 Adjacent sequences:  A110281 A110282 A110283 * A110285 A110286 A110287 KEYWORD nonn AUTHOR Giovanni Teofilatto, Sep 07 2005 EXTENSIONS Extended by Ray Chandler, Sep 07 2005 STATUS approved

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Last modified April 16 18:53 EDT 2021. Contains 343050 sequences. (Running on oeis4.)