This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A278388 Lexicographically earliest sequence such that (i*2^a(i)) AND (j*2^a(j)) = 0 for any distinct i and j (AND stands for the bitwise AND operator). 1
 0, 0, 2, 2, 5, 7, 10, 3, 13, 14, 18, 20, 24, 27, 31, 10, 35, 36, 41, 34, 44, 48, 53, 55, 60, 64, 69, 72, 77, 81, 86, 15, 51, 42, 61, 89, 93, 95, 101, 102, 108, 109, 115, 119, 123, 128, 134, 136, 138, 143, 145, 149, 155, 160, 166, 169, 175, 180, 186, 190, 196 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS By analogy with A275152, this sequence can be obtained by the following algorithm: - we start with a half-open line of empty squares with coordinates X=0, X=1, X=2, etc., - for n=1, 2, 3, ...: we choose the least k such that the polyomino corresponding to n, shifted by k squares to the right, does not overlap one of the previous polyominoes. a(2*k+1) > a(2*k) for any k>0. LINKS Rémy Sigrist, Table of n, a(n) for n = 1..10000 EXAMPLE The following table depicts the first terms, alongside the corresponding polyominoes ("X" denotes a filled square, "_" denotes an empty square): n     n in binary    a(n)    n as a polyomino shifted by a(n) to the right --    -----------    ----    --------------------------------------------- 1     1              0       X 2     10             0       _X 3     11             2         XX 4     100            2         __X 5     101            5            X_X 6     110            7              _XX 7     111            10                XXX 8     1000           3          ___X 9     1001           13                   X__X 10    1010           14                    _X_X 11    1011           18                        XX_X 12    1100           20                          __XX 13    1101           24                              X_XX 14    1110           27                                 _XXX 15    1111           31                                     XXXX 16    10000          10                ____X 17    10001          35                                         X___X 18    10010          36                                          _X__X PROG (PARI) sumn2a = 0; for (n=1, 1 000, a=0; while (bitand(sumn2a, n<

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

Last modified October 23 16:15 EDT 2018. Contains 316529 sequences. (Running on oeis4.)