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 A057324 First member of a prime triple in a p^2 + p - 1 progression. 2
 2, 3, 11, 13, 53, 131, 233, 241, 281, 569, 659, 691, 761, 881, 1693, 2063, 2411, 2521, 2551, 2663, 2729, 2741, 2861, 3089, 4021, 4159, 4201, 4243, 4423, 4793, 6091, 7103, 7229, 7369, 7753, 7829, 8053, 8641, 8669, 9041, 9059, 9539, 9649, 9769, 10513 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There exist no such triples of the form p^2 + p + 1 because each third member is always divisible by 3. Subsequence of A053184. - Pierre CAMI, Sep 13 2013 LINKS Pierre CAMI, Table of n, a(n) for n = 1..10000 EXAMPLE 2 -> 2^2+2-1 = 5 -> 5^2+5-1 = 29 hence the prime triple (2,5,29). MATHEMATICA fmpQ[n_]:=AllTrue[NestList[#^2+#-1&, n, 2], PrimeQ]; Select[Prime[Range[ 1300]], fmpQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 08 2019 *) PROG (PARI) is(n)=for(k=1, 3, if(!isprime(n), return(0)); n=n^2+n-1); 1 \\ Charles R Greathouse IV, Sep 13 2013 CROSSREFS Cf. A053184, A053185, A057325. Sequence in context: A068820 A129670 A215374 * A139052 A076491 A105226 Adjacent sequences:  A057321 A057322 A057323 * A057325 A057326 A057327 KEYWORD nonn AUTHOR Patrick De Geest, Aug 15 2000 STATUS approved

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Last modified April 9 20:46 EDT 2020. Contains 333363 sequences. (Running on oeis4.)