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%I #26 Aug 02 2017 11:00:35
%S 7,17,37,151,607,1217,2437,4877,39019,78041,624331,6243313,174812767,
%T 1398502139,19579029949,39158059901,1957902995053,15663223960427,
%U 156632239604273,3132644792085463,181693397940956857,726773591763827431,7267735917638274313,1148302274986847341457,4593209099947389365831
%N a(1) = 7; a(n) is smallest prime of the form k*a(n-1) + 3, k>0.
%H Robert Israel, <a href="/A214634/b214634.txt">Table of n, a(n) for n = 1..390</a>
%e a(2) = 17 = 2 * 7 + 3.
%e a(3) = 37 = 2 * 17 + 3.
%e a(4) = 151 = 4 * 37 + 3.
%p A214634 := proc(n)
%p option remember;
%p local k;
%p if n = 1 then
%p 7;
%p else
%p for k from 1 do
%p if isprime(k*procname(n-1)+3) then
%p return k*procname(n-1)+3 ;
%p end if;
%p end do:
%p end if;
%p end proc:
%p seq(A214634(n),n=1..20) ; # _R. J. Mathar_, Jul 23 2012
%t spf[n_]:=Module[{k=1},While[!PrimeQ[k*n+3],k++];k*n+3]; NestList[spf,7,25] (* _Harvey P. Dale_, Aug 02 2017 *)
%o (PARI) a=7;for(n=1,200,b=a*n+3;if(isprime(b),a=b;print1(a,", ");next(n=1)))
%Y Cf. A061092, A059411, A214523, A214632, A214633
%K nonn
%O 1,1
%A _Robin Garcia_, Jul 23 2012
%E More terms from _Robert Israel_, Nov 23 2016
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