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A118252
The least positive integer whose reversed binary representation does not occur in the concatenation of the reversed binary representations of all preceding terms.
6
1, 2, 3, 4, 8, 10, 11, 12, 15, 16, 22, 24, 27, 32, 35, 36, 38, 43, 44, 54, 59, 64, 66, 70, 76, 79, 83, 85, 88, 91, 95, 97, 99, 116, 122, 127, 128, 130, 132, 136, 140, 147, 148, 150, 155, 158, 163, 169, 170, 175, 176, 179, 182, 184, 192, 196, 201, 217, 232
OFFSET
1,2
COMMENTS
See the variant A118250 for comments and examples.
LINKS
MATHEMATICA
a = {1}; b = {1}; Do[k = b[[i - 1]] + 1; While[SequenceCount[Flatten@ a, Set[d, Reverse@ IntegerDigits[k, 2]]] != 0, k++]; a = Join[a, d]; AppendTo[b, k], {i, 2, 59}]; b (* Michael De Vlieger, Aug 21 2017 *)
PROG
(PARI) A118252(n, show=0, a=1)={my(c=[a], S=[], L); for(k=1, n, show & print1(a", "); while( setsearch(S, binary(a++)), ); c=concat(binary(a), c); S=[]; for(i=0, #c-L=#binary(a), c[i+1] & for(j=i+L, min(i+L+1, #c), S=setunion(S, Set(t=[vecextract(c, 2^j-2^i)]))))); a} \\ M. F. Hasler, Dec 29 2012
CROSSREFS
Cf. A118248 (variant without reversal), A118250 (the same with a(0)=0), A118251 (concatenation of terms in binary).
Cf. A190896.
Sequence in context: A292113 A082224 A030478 * A047456 A279000 A073465
KEYWORD
easy,nonn
AUTHOR
Leroy Quet, Apr 18 2006
EXTENSIONS
More terms from Graeme McRae, Apr 19 2006
Explicit definition from M. F. Hasler, Dec 29 2012
STATUS
approved