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A121923 a(n) = smallest odd m such that (m^n + (m+2)^n)/2 is prime. 0

%I

%S 2,17,37,4481,101,21601,197,257,106921,401,237161,577,677,

%T 391337974721,815401,1054721,1297,2093801,1601,3122281,3759713,

%U 6265001,2917,3137,12981601,16801793,4357,5477,33396833,2867651480694307162235699968001

%N a(n) = smallest odd m such that (m^n + (m+2)^n)/2 is prime.

%o (PARI) anplusbn(n) = { a=-1; forstep(a=1,n,2,for(x=1,n,y=(a^x+(a+2)^x)/2; if(ispseudoprime(y), print1(y",");break; ) ) ) }

%K nonn

%O 1,1

%A _Cino Hilliard_, Sep 10 2006, corrected Nov 15 2006

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Last modified February 8 07:56 EST 2023. Contains 360136 sequences. (Running on oeis4.)