A226977 Places n where A225867(n) <= 2.

7, 8, 11, 17, 23, 29, 41, 47, 59, 71, 239, 359, 419, 839

Offset: 1

Author

Vladimir Shevelev, Jun 27 2013

Keywords

• nonn
• more

Comments

Except for a(2)=8, all terms are prime.

Is this sequence finite?

There are no other terms up to 86000. - Peter J. C. Moses, Jun 28 2013

There are no more terms up to 10^9. - Charles R Greathouse IV, Nov 25 2014

Crossrefs

Cf. A225867, A049002.

Programs

PARI

is(n)=for(k=2,n\2-1,if(sumdiv(n+k,d,(n+d)%k==0 && d>1)>2, return(0))); n>6 \\ Charles R Greathouse IV, Nov 25 2014