A075572 - OEIS

%I #4 Dec 05 2013 19:55:38

%S 3,5,3,7,5,3,3,5,7,3,11,11,3,3,7,5,5,5,11,13,5,11,17,3,5,13,3,3,7,5,

%T 13,5,5,7,3,13,7,3,13,5,5,7,19,7,7,23,3,5,5,23,17,7,3,3,11,19,3,29,13,

%U 29,7,7,13,3,5,5,3,5,5,13,7,5,5,5,7,5,17,17,3,31,19,3,5,11,19,37

%N Smallest prime divisor of sum of three successive terms pertaining to A075571.

%o (PARI) pr=vector(10000):v=vector(100):v[1]=3:v[2]=5:pr[3]=1:pr[5]=1:for(n=3,100, forprime(p=3,10000,if(!pr[p]&&!isprime(v[n-2]+v[n-1]+p),print1(factor(v[n-2]+v[n-1]+p)[1,1]","):v[n]=p:pr[p]=1:break)))

%Y Cf. A075571.

%K nonn

%O 0,1

%A _Amarnath Murthy_, Sep 25 2002

%E Corrected and extended by _Ralf Stephan_, Mar 27 2003