cp's OEIS Frontend

A357280 Smallest m such that m^k-2 and m^k+2 are prime for k=1..n.

%I A357280 #29 Nov 29 2022 10:31:45
%S A357280 5,9,102795,559838181,27336417022509
%N A357280 Smallest m such that m^k-2 and m^k+2 are prime for k=1..n.
%e A357280 a(3) = 102795 because:
%e A357280 for k = 1; 102795^1-2 = 102793 and 102795^1+2 = 102797, both of which are prime, and
%e A357280 for k = 2; 102795^2-2 = 10566812023 and 102795^2+2 = 10566812027, both of which are prime, and
%e A357280 for k = 3; 102795^3-2 = 1086215442109873 and 102795^3+2 = 1086215442109877, both of which are prime, and
%e A357280 102795 is the smallest number with this property.
%o A357280 (PARI) isok(m,n) = for (k=1, n, if(!isprime(m^k-2) || !isprime(m^k+2), return(0));); return(1);
%o A357280 a(n) = my(m=1); while(!isok(m, n), m++); m; \\ _Michel Marcus_, Nov 14 2022
%Y A357280 Cf. A189051, A245510, A245512, A329727.
%K A357280 nonn,more,hard
%O A357280 1,1
%A A357280 _Kellen Shenton_, Sep 24 2022