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 A317407 The "OOPS" numbers -- numbers with ones in all odd-numbered positions of the binary representation of n. 1
 1, 2, 3, 5, 7, 10, 11, 14, 15, 21, 23, 29, 31, 42, 43, 46, 47, 58, 59, 62, 63, 85, 87, 93, 95, 117, 119, 125, 127, 170, 171, 174, 175, 186, 187, 190, 191, 234, 235, 238, 239, 250, 251, 254, 255, 341, 343, 349, 351, 373, 375, 381, 383, 469, 471, 477, 479, 501 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Here we number positions starting with the most significant digit as position 1, and continue to the right down to the least significant digit. From David A. Corneth, Jul 29 2018: (Start) 1 is in the sequence. If k is in the sequence then so is 2k+1. (End) If A070939(k) is odd and k is in the sequence then so is 2*k. - Robert Israel, Jul 31 2018 LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE 23 is in the sequence because its binary representation is 10111, and it has ones in positions 1,3,5. MAPLE S[1]:= [1]: for n from 2 to 10 do   if n::odd then S[n]:= map(t -> 2*t+1, S[n-1])   else S[n]:= map(t -> (2*t, 2*t+1), S[n-1])   fi od; map(op, [seq(S[i], i=1..10)]); # Robert Israel, Jul 31 2018 PROG (PARI) isok(n) = {my(b=binary(n)); forstep (i=1, #b, 2, if (!b[i], return (0)); ); return (1); } \\ Michel Marcus, Jul 29 2018 CROSSREFS Cf. A032911, A070939. Sequence in context: A194948 A266679 A285257 * A191211 A263133 A254860 Adjacent sequences:  A317404 A317405 A317406 * A317408 A317409 A317410 KEYWORD nonn,base AUTHOR Jeffrey Shallit, Jul 28 2018 STATUS approved

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Last modified August 1 08:54 EDT 2021. Contains 346385 sequences. (Running on oeis4.)