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A113152
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a(1) = 2; a(n) is the smallest prime > a(n-1) such that a(n) + a(n-1) is a fourth power.
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0
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2, 79, 1217, 2879, 7121, 152879, 178897, 12781103, 24233953, 25553183, 29147633, 70852367, 1800921329, 3205490207, 6270364129, 30533756207, 39265770209, 52240479791, 68933130209, 73192853807, 74570506193, 78996293183
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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2+79=3^4, 79+1217=6^4, etc.
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MATHEMATICA
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a=2; s={a}; Do[p=n^4-a; If[p>a&&PrimeQ[p], AppendTo[s, p]; a=p], {n, 2, 3000}]; s
sp4p[n_]:=Module[{k=NextPrime[n]}, While[!IntegerQ[Surd[n+k, 4]], k = NextPrime[ k]]; k]; NestList[sp4p, 2, 21] (* Harvey P. Dale, Apr 02 2018 *)
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PROG
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(PARI) print1(s=a=2); for(n=1, 99, until(isprime(s++^4-a), ); print1(", "a=s^4-a)) \\ M. F. Hasler, Oct 03 2010
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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