The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A214634 a(1) = 7; a(n) is smallest prime of the form k*a(n-1) + 3, k>0. 1
 7, 17, 37, 151, 607, 1217, 2437, 4877, 39019, 78041, 624331, 6243313, 174812767, 1398502139, 19579029949, 39158059901, 1957902995053, 15663223960427, 156632239604273, 3132644792085463, 181693397940956857, 726773591763827431, 7267735917638274313, 1148302274986847341457, 4593209099947389365831 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..390 EXAMPLE a(2) = 17 = 2 * 7 + 3. a(3) = 37 = 2 * 17 + 3. a(4) = 151 = 4 * 37 + 3. MAPLE A214634 := proc(n)     option remember;     local k;     if n =  1 then         7;     else         for k from 1 do             if isprime(k*procname(n-1)+3) then                 return k*procname(n-1)+3 ;             end if;         end do:     end if; end proc: seq(A214634(n), n=1..20) ; # R. J. Mathar, Jul 23 2012 MATHEMATICA spf[n_]:=Module[{k=1}, While[!PrimeQ[k*n+3], k++]; k*n+3]; NestList[spf, 7, 25] (* Harvey P. Dale, Aug 02 2017 *) PROG (PARI)  a=7; for(n=1, 200, b=a*n+3; if(isprime(b), a=b; print1(a, ", "); next(n=1))) CROSSREFS Cf. A061092, A059411, A214523, A214632, A214633 Sequence in context: A090147 A211476 A155007 * A172156 A273947 A140121 Adjacent sequences:  A214631 A214632 A214633 * A214635 A214636 A214637 KEYWORD nonn AUTHOR Robin Garcia, Jul 23 2012 EXTENSIONS More terms from Robert Israel, Nov 23 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 29 21:59 EDT 2020. Contains 337432 sequences. (Running on oeis4.)