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A073826
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Primes of the form Sum_{k=1..n} k^k, i.e., primes in A001923.
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6
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OFFSET
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1,1
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COMMENTS
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a(3) = A001923(10) = 10405071317 and the 45-digit a(4) = A001923(30) have been certified prime with Primo. Any additional terms are too big to include here.
The next term would have over 20000 digits; see A073825 for more information and updates.
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LINKS
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FORMULA
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EXAMPLE
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a(1) = 5 = 1^1 + 2^2 is the smallest prime of the form A001923(n) = sum_{k=1..n} k^k, namely for n = 2 = A073825(1).
a(2) = sum_{k=1..A073825(2)} k^k = 1^1 + 2^2 + 3^3 + 4^4 + 5^5 = 3413, a prime, so 3413 is in this sequence (A073825(2) = 5).
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MATHEMATICA
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PROG
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(PARI) s=0; for(k=1, 1320, s=s+k^k; if(isprime(s), print1(s, ", ")))
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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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