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A100572
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Largest prime p such that the sum of n consecutive primes plus p is equal to (n+1)^3.
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1
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5, 19, 41, 89, 163, 271, 19, 631, 677, 1103, 1237, 1879, 2053, 3049, 3299, 4229, 5333, 5857, 7219, 7607, 9859, 11117, 12577, 14173, 16417, 16223, 20477, 22679, 25409, 26833, 30509, 32771, 36887, 39989, 43759, 47911, 52127, 56237, 60013, 65657, 69691, 74887
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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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a(2)=19 because 3+5+19=3^3;
a(3)=41 because 5+7+11+41=4^3;
a(4)=89 because 5+7+11+13+89=5^3.
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PROG
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(PARI) a(n)=if(n==1, return(5)); my(v=primes(n), s=sum(i=1, n, v[i]), N=(n+1)^3); forprime(p=v[#v]+1, N, if(isprime(N-s), return(N-s)); if(N<s, return(-1)); s+=p-v[1]; v=concat(v[2..n], p)) \\ Charles R Greathouse IV, Jun 03 2013
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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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