2,1

a(5)=10978 because 5^5^5 - 10978 is a prime and 5^5^5 - k is composite for 0<k<10978.

Cf. A103111, A074967, A074966.

Sequence in context: A089041 A059511 A112676 this_sequence A064941 A112612 A129430

Adjacent sequences: A103109 A103110 A103111 this_sequence A103113 A103114 A103115

hard,more,nonn

Farideh Firoozbakht (mymontain(AT)yahoo.com), Mar 04 2005

a(6) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Mar 06 2008