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 A104164 Sophie Germain type primes where 5*Prime[n]=2*Prime[m]+1. 2

%I

%S 7,17,47,107,167,197,257,317,347,557,677,827,947,1097,1217,1307,1367,

%T 1427,1607,1847,1877,2027,2207,2267,2297,2417,2477,2657,2927,3257,

%U 3557,3617,3677,3917,3947,4157,4397,4457,4877,4967,5507,5717,5867,5927,6257

%N Sophie Germain type primes where 5*Prime[n]=2*Prime[m]+1.

%F a(n) = If (5*Prime[n]-1)/2 is prime, then a[m]=(5*Prime[n]-1)/2

%t a = Delete[Union[Table[If [PrimeQ[(5*Prime[n] - 1)/2] == True, (5*Prime[n] - 1)/2, 0], {n, 1, 1000}]], 1]

%Y Cf. Sophie Germain primes: A005384.

%K nonn

%O 1,1

%A _Roger L. Bagula_, Mar 10 2005

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Last modified December 15 11:43 EST 2019. Contains 329999 sequences. (Running on oeis4.)