The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60, we have over 367,000 sequences, and we’ve crossed 11,000 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A168354 Squarefree semiprimes whose binary expansion is palindromic. 1
 15, 21, 33, 51, 65, 85, 93, 119, 129, 219, 341, 365, 381, 403, 427, 471, 511, 633, 717, 771, 843, 951, 1057, 1137, 1241, 1273, 1285, 1317, 1397, 1501, 1651, 1707, 1799, 1967, 2047, 2049, 2661, 2973, 3579, 3687, 3831, 4097, 4321, 4369, 4529, 4593, 4681 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 15 = 3*5 = {1,1,1,1}. 21 = 3*7 = {1,0,1,0,1}. 33 = 3*11 = {1,0,0,0,0,1}. MATHEMATICA f1[n_]:=Reverse[IntegerDigits[n, 2]]==IntegerDigits[n, 2]; f2[n_]:=Last/@FactorInteger[n]=={1, 1}; lst={}; Do[If[f1[n]&&f2[n], AppendTo[lst, n]], {n, 8!}]; lst CROSSREFS Cf. A016041. Intersection of A006995 and A006881. - Michel Marcus, Nov 24 2020 Sequence in context: A043326 A179996 A079814 * A190358 A090999 A123912 Adjacent sequences: A168351 A168352 A168353 * A168355 A168356 A168357 KEYWORD nonn,base AUTHOR Vladimir Joseph Stephan Orlovsky, Nov 23 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 2 09:13 EST 2023. Contains 367516 sequences. (Running on oeis4.)