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A349121
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a(n) is the smallest prime p, such that p + k + k^2 are consecutive primes for 0 <= k <= n, but not for k>n.
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1
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3, 5, 17, 347, 13901, 665111, 128981, 113575727, 2426256797, 137168442221, 4656625081181, 101951758179851, 484511389338941, 221860944705726407
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OFFSET
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1,1
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COMMENTS
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a(n) is the smallest prime followed by exactly n prime gaps in arithmetic progression with a common difference of 2 and starting with prime gap 2.
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LINKS
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EXAMPLE
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a(4)=347, because it is the smallest prime such that 347 + 2 = 349, 349 + 4 = 353, 353 + 6 = 359, 359 + 8 = 367 are 5 consecutive primes.
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MATHEMATICA
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Table[k=2; While[Flatten[k+(s={Range[0, n]})+s^2]!=NextPrime[k, Range[0, n]]||NextPrime[k, n+1]==k+n+1+(n+1)^2, k=NextPrime@k]; k, {n, 7}] (* Giorgos Kalogeropoulos, Nov 10 2021 *)
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PROG
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(PARI) isok(p, n) = my(q=p); for (k=1, n, my(r = p+k+k^2); if (nextprime(q+1) != r, return (0)); q=r); return(1);
a(n) = my(p=2); while (!isok(p, n), p=nextprime(p+1)); p; \\ Michel Marcus, Nov 09 2021
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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