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A364696
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Nonnegative integers k such that the sum of the first k primes is a pentagonal number.
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5
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OFFSET
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1,2
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LINKS
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EXAMPLE
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2 is a term because the sum of the first 2 primes (2 + 3 = 5) is a pentagonal number.
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MATHEMATICA
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A364696list[kmax_]:=Module[{p=0}, Join[{0}, Table[If[IntegerQ[(Sqrt[24(p+=Prime[k])+1]+1)/6], k, Nothing], {k, kmax}]]]; A364696list[25000] (* Paolo Xausa, Oct 06 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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