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 A161388 (Odd) binary palindromes n such that 2*n + 1 is a prime. 2
 1, 3, 5, 9, 15, 21, 33, 51, 63, 65, 99, 119, 153, 165, 189, 219, 231, 273, 341, 443, 455, 495, 561, 585, 645, 765, 771, 891, 975, 1365, 1421, 1533, 1539, 1755, 1911, 2049, 2553, 2661, 2709, 2829, 2925, 3075, 3171, 3339, 3435, 3483, 3579, 4095, 4433, 4529 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..8639 FORMULA a(n) = (A161387(n) - 1)/2. EXAMPLE 67 in binary is 1000011. All binary digits but the rightmost 1 form a palindrome (100001), so therefore (67-1)/2 = 33 is a palindrome. Since 67 is a prime, 33 is in this sequence. MATHEMATICA (Select[Prime@Range[2, 1500], (id=IntegerDigits[(#-1)/2, 2]) == Reverse[id]&]-1)/2 (* Ray Chandler, Jun 09 2009*) fQ[n_] := Block[{id = IntegerDigits[n, 2]}, id == Reverse@ id]; Select[ Range@ 4592, fQ@# && PrimeQ[2 # + 1] &] (* Robert G. Wilson v, Jun 09 2009 *) PROG (PARI) forprime(p=3, 100000, t=binary((p-1)/2); if(t==vector(#t, x, t[ #t+1-x]), print1((p-1)/2, ", "))) \\ Hagen von Eitzen, Jun 10 2009 (MAGMA) [ n: p in PrimesInInterval(3, 9100) | s eq Reverse(s) where s is Intseq(n, 2) where n is (p-1) div 2]; // Klaus Brockhaus, Jun 09 2009 CROSSREFS Cf. A161387. Sequence in context: A045602 A029470 A182185 * A229552 A029518 A061954 Adjacent sequences:  A161385 A161386 A161387 * A161389 A161390 A161391 KEYWORD base,nonn AUTHOR Leroy Quet, Jun 08 2009 EXTENSIONS Extended by Hagen von Eitzen, Ray Chandler, Klaus Brockhaus and Robert G. Wilson v, Jun 09 2009 STATUS approved

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Last modified February 15 22:28 EST 2019. Contains 320138 sequences. (Running on oeis4.)