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 A367992 #13 Mar 23 2024 20:59:00 %S A367992 4,9,35,187,221,2323,120137,1021039,19399403,223092899,6469693261, %T A367992 200560490167,7420738134851,304250263527253,39248283995010137, %U A367992 614889782588491463,65178316954380089519,3845520700308425278201,117288381359406970983337,7858321551080267055879161 %N A367992 Smallest nonprime that is the n-th prime plus a multiple of the (n-1)-st primorial. %H A367992 Alon Amit, <a href="https://www.quora.com/How-do-you-find-the-smallest-positive-integer-n-so-7-30n-is-not-a-prime-number">How do you find the smallest positive integer n so 7+30n is not a prime number?</a>, Quora, November 22, 2023. %e A367992 For n = 1, the n-th prime (2) plus a multiple m of the (n-1) primorial (1) is 2+m, giving the smallest nonprime, a(1)=4, when m=2. %e A367992 For n = 4, the n-th prime (7) plus a multiple m of the (n-1) primorial (30) is 7+30m, giving the smallest nonprime, a(4)=187, when m=6. %t A367992 a[n_] := Module[{p = Prime[n], r = Product[Prime[i], {i, 1, n - 1}]}, While[p += r; PrimeQ[p]]; p]; Array[a, 20] (* _Amiram Eldar_, Dec 07 2023 *) %Y A367992 Cf. A000040, A002110. %K A367992 nonn %O A367992 1,1 %A A367992 _Don N. Page_, Dec 07 2023