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Numbers k such that k!! - prime(k) is prime.
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%I #9 Jan 04 2025 14:01:12

%S 14,20,54,56,144,206,212,436,1610,4450,4512,5202,6684,14318

%N Numbers k such that k!! - prime(k) is prime.

%C There is no further term up to 8800. - _Farideh Firoozbakht_, Aug 19 2005

%e 14 is a term since 14!! - prime(14) = 645120 - 43 = 645077 is prime.

%t Select[Range[1610], PrimeQ[ #!! - Prime[ # ]] &]

%Y Cf. A006882, A007749, A064401.

%K nonn,more

%O 1,1

%A Amineh Farzannia (afarzannia(AT)yahoo.com), Jul 06 2005

%E More terms from _Farideh Firoozbakht_, Aug 19 2005

%E Name corrected, term 3 removed, and a(14) from _Michael S. Branicky_, Jan 03 2025