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a(n) = least prime of the form 2^m - 2^n + 1.
3

%I #11 Jan 12 2020 13:35:47

%S 2,3,5,549755813881,17,97,193,140737488355201,257,7681,15361,

%T 134215681,12289,8380417,114689

%N a(n) = least prime of the form 2^m - 2^n + 1.

%C a(15) = 2^447 - 2^15 + 1 is too large to be represented in the data.

%H Hugo Pfoertner, <a href="/A331205/b331205.txt">Table of n, a(n) for n = 0..62</a>

%e See A331204.

%o (PARI) for(n=0,14, for(m=n+1,oo, k=2^m-2^n+1; if(isprime(k), print1(k,", "); break)))

%Y Cf. A181692, A331204 (corresponding values of m).

%K nonn

%O 0,1

%A _Hugo Pfoertner_, Jan 12 2020