



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
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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



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



KEYWORD

nonn


AUTHOR



EXTENSIONS

a(13) corrected and terms a(14) onward provided by Max Alekseyev, Aug 25 2013


STATUS

approved



