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 A330409 #10 Apr 27 2022 18:36:19
%S A330409 22,51,145,287,1717,2147,3151,5017,11051,13207,16801,20827,26867,
%T A330409 63551,68587,71177,76501,96647,112477,147737,159251,232657,237407,
%U A330409 308947,314417,342487,433897,480251,587501,602617,722107,772927,834401,861467,879751,907537,945257,1155887,1177051
%N A330409 Semiprimes of the form p(6p - 1).
%H A330409 Harvey P. Dale, <a href="/A330409/b330409.txt">Table of n, a(n) for n = 1..1000</a>
%F A330409 a(n) = A049452(A158015(n)) = p(6p - 1) with p = A158015(n).
%e A330409 A158015(1) = 2 is the smallest prime p such that 6p - 1 = 12 - 1 = 11 is also prime, whence a(1) = A049452(2) = 2*(6*2 - 1) = 22.
%e A330409 prime(5) = 11 is the smallest prime not in A024898 or A158015, because 6p - 1 is not a prime, therefore A049452(11) = 11*(6*11 - 1) is not in the sequence, and idem for A049452(13).
%e A330409 But prime(7) = 17 is in A024898 and A158015, so a(5) = A024898(A158015(5)) = A024898(17) = 17*(6*17 - 1).
%t A330409 Select[Table[p(6p-1),{p,500}],PrimeOmega[#]==2&] (* _Harvey P. Dale_, Apr 27 2022 *)
%o A330409 (PARI) [p*(6*p-1) | p<-primes(99), isprime(6*p-1)]
%Y A330409 Cf. A024898 (6n-1 is prime), A158015 (primes), A049452 = {n(6n-1)}.
%Y A330409 Complement of A255584 = A033570(A130800) (semiprimes (2n+1)(3n+1)) in A245365 (primes of the form n(3n-1)/2).
%K A330409 nonn
%O A330409 1,1
%A A330409 _M. F. Hasler_, Dec 13 2019