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Prime(k), where k is such that (Sum_{i=1..k} prime(i)^10) / k is an integer.
1

%I #21 Jul 09 2023 23:13:36

%S 2,1723,504017,707602177,3221410523,50872396681,502768196591,

%T 809590307027,7067369025727,67826487302603,8107773185261209

%N Prime(k), where k is such that (Sum_{i=1..k} prime(i)^10) / k is an integer.

%C a(11) > 80562077557177. - _Bruce Garner_, Mar 06 2021

%H OEIS Wiki, <a href="https://oeis.org/wiki/Sums_of_primes_divisibility_sequences">Sums of powers of primes divisibility sequences</a>

%F a(n) = prime(A131264(n))

%e a(2) = 1723, because 1723 is the 269th prime and the sum of the first 269 primes^10 = 5093580907935902678630090684087692 when divided by 269 equals 18935245010914136351784723732668 which is an integer.

%t t = {}; sm = 0; Do[sm = sm + Prime[n]^10; If[Mod[sm, n] == 0, AppendTo[t, Prime[n]]], {n, 100000}]; t (* Derived from A217599 *)

%o (PARI) is(n)=if(!isprime(n),return(0)); my(t=primepi(n),s); forprime(p=2,n,s+=Mod(p,t)^10); s==0 \\ _Charles R Greathouse IV_, Nov 30 2013

%o (PARI) S=n=0;forprime(p=1,,(S+=p^10)%n++||print1(p",")) \\ _M. F. Hasler_, Dec 01 2013

%Y Cf. A085450 (smallest m > 1 such that m divides Sum_{k=1..m} prime(k)^n).

%Y Cf. A007504, A045345, A171399, A128165, A233523, A050247, A050248.

%Y Cf. A024450, A111441, A217599, A128166, A233862, A217600, A217601.

%K nonn,more

%O 1,1

%A _Robert Price_, Dec 04 2013

%E a(9)-a(10) from _Bruce Garner_, Mar 06 2021

%E a(11) from _Paul W. Dyson_, Jul 09 2023

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Last modified September 20 21:38 EDT 2024. Contains 376078 sequences. (Running on oeis4.)