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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A124241 Terms of A068563 that are not terms of A124240. 3
 136, 408, 620, 680, 820, 1224, 1240, 1314, 2040, 2312, 2460, 2480, 2628, 2856, 3100, 3400, 3672, 3924, 3942, 4100, 4112, 4656, 4960, 5304, 5334, 5784, 6120, 6200, 6820, 6936, 7380, 7480, 7848, 7884, 8224, 8568, 9020, 9060, 9198, 9492, 9920, 10200, 10668, 11016, 11560, 11568, 11826, 12300, 12336, 12400, 13140, 13640 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A068563 contains A124240 as a subsequence. This sequence gives their set difference. Note that a(2) = 3*a(1) and a(4) = 5*a(1). a(6) = 1224 = 9*a(1), a(7) = 1240 = 2*a(3), a(8) = 1314, a(9) = 2040 = 15*a(1), a(10) = 2312 = 17*a(1), a(11) = 2460 = 3*a(5), a(12)= 2480 = 4*a(3), a(13) = 2856 = 21*a(1). Numbers k such that there exists a(n) = k*a(1) are k = {1, 3, 5, 9, 15, 17, 21, ...}. Many but not all terms belong to A124276. LINKS Table of n, a(n) for n=1..52. PROG (PARI) for(n=1, 10^5, m=n\2^valuation(n, 2); if( Mod(n, znorder(Mod(2, m))), next); p=factor(n)[, 1]; g=1; for(i=1, #p, if( Mod(n, p[i]-1), g=0; break) ); if(g, next); print1(n, ", ") ) /* Alekseyev */ CROSSREFS Cf. A124240, A124239, A068563, A124276, A064896. Sequence in context: A247439 A183635 A116223 * A235198 A235191 A076331 Adjacent sequences: A124238 A124239 A124240 * A124242 A124243 A124244 KEYWORD nonn AUTHOR Alexander Adamchuk, Oct 22 2006, Oct 27 2006 EXTENSIONS a(13) corrected and terms a(14) onward provided by Max Alekseyev, Aug 25 2013 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 October 3 16:29 EDT 2023. Contains 365868 sequences. (Running on oeis4.)