A214633
a(1)=2; a(n) is smallest prime of the form k*a(n-1) + 3, k>0.
Original entry on oeis.org
2, 5, 13, 29, 61, 491, 3931, 15727, 157273, 314549, 4403689, 17614759, 387524701, 5425345817, 119357607977, 9787323854117, 78298590832939, 1722568998324661, 68902759932986443, 4685387675443078127, 318606361930129312639, 637212723860258625281
Offset: 1
-
A214633 := proc(n)
option remember;
local k;
if n = 1 then
2;
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(A214633(n),n=1..20) ; # R. J. Mathar, Jul 23 2012
A214634
a(1) = 7; a(n) is smallest prime of the form k*a(n-1) + 3, k>0.
Original entry on oeis.org
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
Offset: 1
a(2) = 17 = 2 * 7 + 3.
a(3) = 37 = 2 * 17 + 3.
a(4) = 151 = 4 * 37 + 3.
-
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
-
spf[n_]:=Module[{k=1},While[!PrimeQ[k*n+3],k++];k*n+3]; NestList[spf,7,25] (* Harvey P. Dale, Aug 02 2017 *)
-
a=7;for(n=1,200,b=a*n+3;if(isprime(b),a=b;print1(a,", ");next(n=1)))
Showing 1-2 of 2 results.