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 A121068 #22 Oct 12 2024 21:32:25 %S A121068 0,3,27,30,33,48,57,60,72,75,78,108,117,123,135,150,162,192,198,207, %T A121068 228,243,270,300,303,312,342,345,390,408,417,423,435,480,498,507,510, %U A121068 513,543,552,555,573,618,633,642,645,657,675,705,723,732,738,747,750,780 %N A121068 Numbers k such that 8*k^2 + 7 is prime. %C A121068 All terms are multiples of 3. - _Zak Seidov_, Aug 11 2006 %C A121068 A201704 is primes of form 8*k^2+7. _James C. McMahon_, Oct 12 2024 %e A121068 If k=135 then 8*k^2 + 7 = 145807 (prime). %p A121068 a:=proc(n) if isprime(8*n^2+7)=true then n else fi end: seq(a(n),n=0..1000); # _Emeric Deutsch_, Aug 11 2006 %t A121068 Select[Range[0,780],PrimeQ[8#^2+7]&] (* _James C. McMahon_, Oct 12 2024 *) %o A121068 (Magma) [ n: n in [0..1500] | IsPrime(8*n^2 + 7) ]; // _Vincenzo Librandi_, Jan 31 2011 %o A121068 (PARI) is(n)=isprime(8*n^2+7) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A121068 Cf. A007522, A201704. %K A121068 nonn,easy %O A121068 1,2 %A A121068 _Parthasarathy Nambi_, Aug 10 2006 %E A121068 More terms from _Emeric Deutsch_ and _Joshua Zucker_, Aug 11 2006