Search: id:A057821 Results 1-1 of 1 results found. %I A057821 %S A057821 1,5,9,5,21,29,9,5,9,17,45,161,165,269,285,17,45,233,9,17,321,317, %T A057821 633,677,405,437,189,1385,69,209,9,641,849,137,45,401,381,437,1965, %U A057821 2201,741,1493,573,857,1485,5297,2709,161,465,473,1269,4805,789 %N A057821 Useful safe primes: a(n) = least nonnegative integer k such that 2^n - k is prime and (2^n-k-1)/2 is also prime. %Y A057821 Cf. A013603. %Y A057821 Sequence in context: A117014 A010720 A094389 this_sequence A133742 A134879 A051158 %Y A057821 Adjacent sequences: A057818 A057819 A057820 this_sequence A057822 A057823 A057824 %K A057821 nonn %O A057821 3,2 %A A057821 Warren Smith (wds(AT)research.nj.nec.com), Nov 23 2000 Search completed in 0.001 seconds