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A340770 Indices k of prime numbers such that prime(k)-2 and prime(k)^2-2 are both prime numbers. 1

%I #16 Feb 19 2021 20:33:56

%S 3,4,6,8,14,18,27,34,65,82,99,141,172,177,191,202,216,226,319,333,337,

%T 445,470,476,496,552,559,564,578,602,637,672,829,850,863,871,949,1005,

%U 1065,1075,1190,1199,1231,1239,1306,1329,1446,1450,1529,1619,1635,1643

%N Indices k of prime numbers such that prime(k)-2 and prime(k)^2-2 are both prime numbers.

%C This sequence is a subsequence of A107770.

%H François Marques, <a href="/A340770/b340770.txt">Table of n, a(n) for n = 1..10000</a>

%e 6 is in the sequence since prime(6)=13 and 13-2=11 and 13^2-2=167 are both prime numbers.

%o (PARI) lista(n) = {my(l=List,k=1); while(#l<n,k++; if(isprime(prime(k)-2) && isprime(prime(k)^2-2),listput(l,k))); return(l)};

%Y Cf. A107770, A292201.

%K nonn,easy

%O 1,1

%A _François Marques_, Jan 20 2021

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Last modified April 18 20:26 EDT 2024. Contains 371781 sequences. (Running on oeis4.)