A374664 Nonnegative numbers whose binary expansion has no ones in common with some of its cyclic shifts.
0, 2, 4, 8, 9, 10, 12, 16, 17, 18, 20, 24, 32, 33, 34, 35, 36, 40, 42, 48, 49, 56, 64, 65, 66, 67, 68, 72, 73, 74, 76, 80, 82, 84, 96, 97, 100, 112, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 140, 144, 145, 146, 148, 150, 152, 153, 160, 161, 162
Offset: 1
Examples
The first terms, with their binary expansion and an appropriate cyclic shift, are: n a(n) bin(a(n)) cyc -- ---- --------- ------ 1 0 0 0 2 2 10 01 3 4 100 001 4 8 1000 0001 5 9 1001 0110 6 10 1010 0101 7 12 1100 0011 8 16 10000 00001 9 17 10001 00110 10 18 10010 00101 11 20 10100 01001 12 24 11000 00011 13 32 100000 000001 14 33 100001 000110 15 34 100010 000101 16 35 100011 011100
Programs
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PARI
is(n) = { my (x = max(exponent(n), 0), s = n); for (i = 0, x, s = (s >> 1) + if (s%2, 2^x, 0); if (bitand(s, n)==0, return (1););); return (0); }
Comments