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 A108420 #9 Jan 04 2025 14:01:12 %S A108420 14,20,54,56,144,206,212,436,1610,4450,4512,5202,6684,14318 %N A108420 Numbers k such that k!! - prime(k) is prime. %C A108420 There is no further term up to 8800. - _Farideh Firoozbakht_, Aug 19 2005 %e A108420 14 is a term since 14!! - prime(14) = 645120 - 43 = 645077 is prime. %t A108420 Select[Range[1610], PrimeQ[ #!! - Prime[ # ]] &] %Y A108420 Cf. A006882, A007749, A064401. %K A108420 nonn,more %O A108420 1,1 %A A108420 Amineh Farzannia (afarzannia(AT)yahoo.com), Jul 06 2005 %E A108420 More terms from _Farideh Firoozbakht_, Aug 19 2005 %E A108420 Name corrected, term 3 removed, and a(14) from _Michael S. Branicky_, Jan 03 2025