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 A076134 #28 Jun 09 2025 19:45:50 %S A076134 0,1,2,3,4,5,9,12,17,26,76,379,438,1695,6709,13313,18504,19021,24488, %T A076134 45552,49085,65451 %N A076134 Numbers k such that 3*k! - 1 is prime. %C A076134 a(23) > 80000. - _Serge Batalov_, Jun 09 2025 %e A076134 k = 5 is here because 3*5! - 1 = 359 is prime. %p A076134 for n from 0 to 1000 do if isprime(3*n! - 1) then print(n) end if end do; %t A076134 Select[Range[0, 10^3], PrimeQ[3 #! - 1] &] (* _Robert Price_, May 27 2019 *) %o A076134 (PARI) isok(n) = isprime(3*n! - 1); \\ _Michel Marcus_, Nov 13 2016 %o A076134 (PFGW) ABC2 3*$a!+1 %o A076134 a: from 1 to 1000 // _Jinyuan Wang_, Feb 04 2020 %Y A076134 Cf. A051915, A076134. %Y A076134 Cf. A002982, A076133, A099350, A099351, A180627, A180628, A180629, A180630, A180631. %K A076134 nonn,more %O A076134 1,3 %A A076134 Phillip L. Poplin (plpoplin(AT)bellsouth.net), Oct 30 2002 %E A076134 a(15)-a(21) from _Roger Karpin_, Nov 13 2016 %E A076134 a(22) from _Serge Batalov_, Jun 08 2025