cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A217313 Numbers for which there exist a base in which n contains more 1's than in binary.

Original entry on oeis.org

4, 8, 16, 32, 40, 64, 112, 128, 129, 130, 148, 256, 257, 258, 259, 260, 274, 280, 292, 328, 336, 337, 352, 364, 388, 392, 400, 448, 512, 580, 608, 656, 768, 769, 770, 772, 776, 784, 832, 850, 1024, 1025, 1026, 1030, 1032, 1036, 1040, 1042, 1048, 1056, 1057, 1058, 1060, 1064, 1065
Offset: 1

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Author

Benedikt Otten, Mar 17 2013

Keywords

Comments

Numbers n for which A062843(n) != A000120(n).
Every number of the form 2^m with m > 1 is included in the list.

Examples

			40 is 111 (3 ones) in base 3 and 101000 (2 ones) in base 2, therefore it is in the sequence.
		

Programs

  • Mathematica
    Select[Table[n, {n, 1, 1000}], Max[Table[Count[IntegerDigits[#, b], 1], {b, 2, # + 1}]] != Count[IntegerDigits[#, 2], 1] &]
  • PARI
    ones(n, b)=my(s); while(n, if(n%b==1, s++); n\=b); s
    is(n)=if(n<4, return(0)); my(m=hammingweight(n), b=2); while(b++^(m-1)m,return(1))); 0 \\ Charles R Greathouse IV, Mar 19 2013