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Primes of the form 5^k-2.
1

%I #9 Oct 18 2021 13:21:36

%S 3,23,6103515623,1490116119384765623,

%T 88817841970012523233890533447265623,

%U 11754943508222875079687365372222456778186655567720875215087517062784172594547271728515623,44841550858394146269559346665277316200968382140048504696226185084473314645947539247572422027587890623

%N Primes of the form 5^k-2.

%C See the sequence A109080 for the corresponding exponents k.

%C The number a(3) = 6103515623 is also in A095304, A104090 and A128472.

%F a(n) = 5^A109080(n)-2.

%o (PARI) for(i=0,999, ispseudoprime(t=5^i-2) & print1(t","))

%Y Cf. A109080.

%K nonn,less

%O 1,1

%A _M. F. Hasler_, Jan 30 2012