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 A079471 Fixed points of reversed binary words in reversed lexicographic order. 1
 0, 1, 6, 10, 18, 34, 60, 66, 92, 108, 116, 130, 156, 172, 180, 204, 212, 228, 258, 284, 300, 308, 332, 340, 356, 396, 404, 420, 452, 514, 540, 556, 564, 588, 596, 612, 652, 660, 676, 708, 780, 788, 804, 836, 900, 1026, 1052, 1068, 1076, 1100, 1108, 1124 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS These are 0 and the words where the bit count is 2^i where i is the index of the lowest set bit. LINKS Joerg Arndt, Fxtbook, section 1.26.4 "The sequence of fixed points", p.73-74 EXAMPLE Zero is a fixed point: 0: ........... The next few in decimal and binary form (dots for zeros), lowest (rightmost) bit has index zero are: 1: ............1 6: ..........11. 10: ........1.1. 18: .......1..1. 34: ......1...1. 60: ......1111.. 66: .....1....1. 92: .....1.111.. 108: ....11.11.. 116: ....111.1.. 130: ...1.....1. PROG (C++): /* Generate the binary words lex order:   start with zero and get successive elements via */ inline ulong prev_lexrev(ulong x) /* Return previous word in (reversed) lex order. */ {   ulong x0 = x & -x;   if ( x & (x0<<1) ) x ^= x0;   else { x0 ^= (x0<<1); x ^= x0; x |= 1; }   return x; } /* To extract the fixed points, select those where    the following function returns a nonzero value: */ ulong is_lexrev_fixed_point(ulong x) /* Return whether x is a fixed point in the prev_lexrev() - sequence */ {   if ( x & 1 ) { if ( 1==x ) return 1; else return 0; }   else   {     ulong w = bit_count(x);     if ( w != (w & -w) ) return 0;     if ( 0==x ) return 1; return ( (x & -x) & w );   } } CROSSREFS Sequence in context: A032641 A293555 A169873 * A134351 A307458 A287273 Adjacent sequences:  A079468 A079469 A079470 * A079472 A079473 A079474 KEYWORD easy,nonn AUTHOR Joerg Arndt, Jan 15 2003 STATUS approved

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Last modified February 22 14:33 EST 2020. Contains 332136 sequences. (Running on oeis4.)