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 A106155 Numbers k > 2 such that prime(k)# + (prime(k+1))^2 or prime(k+1)# - (prime(k+2))^2 is prime or both are primes. 1
 3, 4, 5, 6, 7, 10, 12, 13, 19, 26, 28, 41, 66, 73, 76, 78, 85, 371, 437, 513, 661, 726, 924, 1063, 1331, 1380, 1422, 1602, 1947, 1963, 3091, 3295, 3401 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..33. EXAMPLE 2*3*5 + 7*7 = 79 prime as 2*3*5*7 - 11*11 = 89 prime so a(1)=3. 2*3*5*7 + 11*11 = 331 prime as 2*3*5*7*11 -13*13 = 2141 prime so a(2)=4. 2*3*5*7*11 + 13*13 = 2479 = 37*67 composite. 2*3*5*7*11*13 - 17*17 = 29471 prime so a(3)=5. CROSSREFS Cf. A002110, A038767. Sequence in context: A159973 A359772 A158008 * A271376 A087190 A085038 Adjacent sequences: A106152 A106153 A106154 * A106156 A106157 A106158 KEYWORD more,nonn AUTHOR Pierre CAMI, May 08 2005 EXTENSIONS a(20)-a(30) from Donovan Johnson, Apr 27 2008 a(31)-a(33) from Michael S. Branicky, Jun 09 2023 STATUS approved

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Last modified March 4 22:06 EST 2024. Contains 370532 sequences. (Running on oeis4.)