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A119751
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a(1) = 1; a(n) = first odd number greater than a(n-1) such that a(n) + a(i) + 1 is prime for all i=1,2,...,n.
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9
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1, 3, 9, 69, 429, 4089, 86529, 513099, 913569, 7914339, 6593621379, 9366241599, 456246278469, 4565283812559
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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Table[If[n == 1, a[1] = 1, j = a[n - 1] + 2; While[a[n] = j; !
AllTrue[Table[a[i] + a[n] + 1, {i, 1, n}], PrimeQ], j += 2]; j]
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PROG
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(PARI) isok(va, k, n) = if (isprime(2*k+1), for (i=1, n-1, if (! isprime(va[i]+k+1), return(0))); return(1));
lista(nn) = my(va=vector(nn)); va[1]=1; for (n=2, nn, my(k=va[n-1]+2); while (!isok(va, k, n), k+=2); va[n] = k); va; \\ Michel Marcus, Mar 07 2023
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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