This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A372238 #45 May 06 2024 16:23:24
%S A372238 2,2,4,170,9860,23450,56980,56980,6723767050,48276858630,
%T A372238 77460393371130,97581361797920,97581361797920,1269928100726715430
%N A372238 Least number m such that 9*k*m+1 is prime for k=1..n.
%H A372238 David A. Corneth, <a href="/A372238/a372238.gp.txt">PARI program</a>
%F A372238 If A088250(n) is divisible by 9, then a(n) = A088250(n) / 9. - _Jason Yuen_, Apr 25 2024
%e A372238 a(1) = 2, because 9*1*2 + 1 = 19 is prime and no lesser number has this property.
%t A372238 p[m_, n_] := AllTrue[Range[n], PrimeQ[9*#*m + 1] &];
%t A372238 a[n_] := a[n] = Module[{m = 1}, While[! p[m, n], m++]; m]
%t A372238 Table[a[n], {n, 1, 9}] (* _Robert P. P. McKone_, May 02 2024 *)
%o A372238 (PARI) is(n,m)=my(u=vector(n,k,9*k*m+1));for(i=1,n,if(!isprime(u[i]),return(0)));1
%o A372238 a(n)=my(pas=1);if(n<15,if(n>2,pas=factorback(primes(primepi(n)));pas/=3;my(m=pas));forstep(m=pas,+oo,pas,if(is(n,m),return(m))))
%o A372238 (PARI) See PARI link
%Y A372238 Cf. A372188, A088250.
%K A372238 nonn,hard,more
%O A372238 1,1
%A A372238 _Jean-Marc Rebert_, Apr 23 2024
%E A372238 a(11)-a(13) from _David A. Corneth_, Apr 24 2024
%E A372238 a(14) from _Jason Yuen_, Apr 25 2024