login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128165 Numbers n such that n divides 1 plus the sum of the first n primes. 93

%I

%S 1,2,6,10,20,22,28,155,488,664,992,6162,7840,7975,8793,18961,32422,

%T 148220,231625,332198,459121,462932,2115894,8108930,10336641,11789731,

%U 15500046,23483195,46571611,48582404,77033887,105390951,132421841,229481560,1224959312

%N Numbers n such that n divides 1 plus the sum of the first n primes.

%C a(44) > 4.4*10^10. - _Robert Price_, Dec 15 2013

%H Robert Price, <a href="/A128165/b128165.txt">Table of n, a(n) for n = 1..43</a>

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

%t k = 0; s = 1; p = 2; A128165 = {}; While[k < 247336000, If[Mod[s += p, ++k] == 0, AppendTo[A128165, k]; Print[{k, p}]]; p = NextPrime@ p]; A128165

%o (PARI) is(n)=sum(i=1,n,prime(i),1)%n==0 \\ _Charles R Greathouse IV_, Nov 07 2014

%o (PARI) n=0; s=1; forprime(p=2,1e9, s+=p; if(s%n++==0, print1(n", "))) \\ _Charles R Greathouse IV_, Nov 07 2014

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

%K hard,nonn

%O 1,2

%A _Alexander Adamchuk_, Feb 22 2007, extended Feb 22 2007

%E More terms from _Ryan Propper_, Apr 05 2007

%E a(34) from _Robert G. Wilson v_

%E a(35) from _Robert Price_, Dec 15 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 16 12:52 EDT 2019. Contains 328060 sequences. (Running on oeis4.)