A095184 - OEIS

%I #8 Aug 19 2019 03:22:25

%S 3,5,11,31,59,103,181,283,359,727,1249,1373,1447,1693,1951,2609,2927,

%T 3163,3407,3541,3967,4259,4733,5231,6121,6703,7309,7927,8783,9001,

%U 9227,10243,12601,13697,15643,17431,20149,23603,23929,25933,30431,31147

%N a(1) = 3; for n > 1 a(n) is the least prime of form a(n-1) + k*prime(n-1) with k > 0.

%e For n = 4 we have a(n-1) = a(3) = 11, prime(n-1) = prime(3) = 5; a(3) + k*prime(3) = 11 + k*5 gives 16 for k = 1, 21 for k = 2, 26 for k = 3 and prime 31 for k = 4, hence a(4) = 31.

%o (PARI) {for(n=1,42,if(n==1,a=3,p=prime(n-1);k=1;while(!isprime(r=a+k*p),k++);a=r);print1(a,","))}

%Y Cf. A085041. [_R. J. Mathar_, Sep 04 2008]

%K nonn,easy

%O 1,1

%A _Amarnath Murthy_, Jun 02 2004

%E Edited and extended by _Klaus Brockhaus_, Jun 04 2004