A158682 Numbers n such that 1 plus the sum of the first n primes is divisible by n+1.

2, 6, 224, 486, 734, 50046, 142834, 170208, 249654, 316585342, 374788042, 2460457826, 2803329304, 6860334656, 65397031524, 78658228038

Offset: 1

Author

Ctibor O. Zizka, Mar 24 2009

Keywords

• nonn
• more

Comments

a(17) > pi(4*10^12). - Donovan Johnson, Jul 02 2010

Crossrefs

Cf. A153022, A045345, A128165, A000040, A007504, A111441.

Programs

Mathematica

k = 0; s = 1; p = 2; lst = {}; While[k < 10^9, s = s + p; If[ Mod[s, ++k + 1] == 0, AppendTo[lst, k]; Print[{k, p}]]; p = NextPrime@ p]

Extensions

a(6)-a(8) from R. J. Mathar, Mar 26 2009

a(9)-a(11) from Donovan Johnson, Nov 15 2009

a(12)-a(13) from Ray Chandler, May 31 2010

a(14)-a(16) from Donovan Johnson, Jul 02 2010