Search: id:A023330 Results 1-1 of 1 results found. %I A023330 %S A023330 89,63419,127139,405269,810809,1069199,1122659,1178609,1333889,1598699, %T A023330 1806089,1958249,2164229,2245319,2329469,2606069,2848949,3241289,3339989, %U A023330 3784199,3962039,4088879,4328459,4444829,4658939,4664249,4894889,4897709 %N A023330 Numbers n such that n remains prime through 5 iterations of function f(x) = 2x + 1. %t A023330 Select[Prime[Range[10^5]], PrimeQ[a1=2*#+1]&&PrimeQ[a2=2*a1+1]&&PrimeQ[a3=2*a2+1]&&PrimeQ[a4=2*a3+1]&&PrimeQ[\ a5=2*a4+1] &] (from Vladimir Orlovsky (4vladimir(AT)gmail.com), May 01 2008) %Y A023330 Cf. (A005384 and A005385), A007700, A023272, A023302, A057331, A005602. %Y A023330 Sequence in context: A086695 A056568 A167398 this_sequence A059766 A033513 A128872 %Y A023330 Adjacent sequences: A023327 A023328 A023329 this_sequence A023331 A023332 A023333 %K A023330 nonn %O A023330 1,1 %A A023330 David W. Wilson (davidwwilson(AT)comcast.net) Search completed in 0.002 seconds