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.

Showing 1-3 of 3 results.

A248478 Evil numbers (A001969) becoming odious (A000069) if any digit is deleted (zeros allowed).

Original entry on oeis.org

12, 17, 18, 24, 27, 48, 71, 72, 77, 78, 111, 113, 114, 116, 119, 141, 144, 149, 169, 216, 221, 222, 225, 226, 228, 252, 255, 281, 282, 288, 311, 325, 387, 411, 414, 441, 442, 444, 447, 449, 474, 479, 497, 525, 526, 550, 556, 559, 562, 619, 621, 622, 649, 674
Offset: 1

Views

Author

Vladimir Shevelev, Oct 07 2014

Keywords

Examples

			149 is in the sequence, since 149 = 2^7 + 2^4 + 2^2 + 1 is evil, while 49, 19 and 14 are odious.

Links

Crossrefs

Cf. A000069, A001969, A248642, A248644, A248659.

Extensions

More terms from Peter J. C. Moses, Oct 11 2014

A248659 Odious numbers (A000069) becoming evil (A001969) if any digit is deleted (zeros allowed).

Original entry on oeis.org

35, 50, 55, 56, 59, 69, 93, 100, 127, 157, 158, 185, 200, 203, 230, 233, 234, 239, 290, 299, 309, 333, 334, 336, 339, 346, 400, 403, 405, 406, 433, 436, 453, 458, 460, 463, 465, 466, 468, 517, 518, 548, 577, 578, 583, 653, 665, 666, 668, 727, 757, 758, 772
Offset: 1

Views

Author

Vladimir Shevelev, Oct 11 2014

Keywords

Examples

			127 is in the sequence, since it is odious, while numbers 27,17,12 are evil.

Links

Crossrefs

Cf. A000069, A001969, A248478, A248642, A248644.

Programs

  • Mathematica
    odiousQ:=OddQ[First[DigitCount[#,2]]]&;
Select[Range[10,1000],odiousQ[#]&&Apply[And,Map[!odiousQ[FromDigits[#]]&,Subsets[#,{Length[#]-1}]&[IntegerDigits[#]]]]&] (* Peter J. C. Moses, Oct 11 2014 *)

Extensions

More terms from Peter J. C. Moses, Oct 11 2014

A248644 Evil numbers (A001969) remaining evil if any digit is deleted (zeros allowed).

Original entry on oeis.org

0, 3, 5, 6, 9, 30, 33, 36, 39, 53, 60, 63, 65, 66, 90, 95, 96, 99, 105, 120, 172, 175, 177, 178, 180, 209, 240, 243, 277, 300, 303, 306, 330, 340, 343, 360, 363, 366, 390, 396, 399, 430, 480, 483, 485, 486, 533, 534, 543, 571, 600, 603, 605, 606, 630, 633, 636, 658, 660, 663
Offset: 1

Views

Author

Vladimir Shevelev, Oct 10 2014

Keywords

Comments

Dual variant of A248642.
Although for numbers >9 we never put 0 instead of the removed digit, we include single-digit numbers 0,3,5,6,9 since, e.g., 3=03, etc.

Examples

			172 is in the sequence since 172,72,12,17 are evil.

Crossrefs

Cf. A001969, A248478, A248642, A248659.

Programs

  • Sage
    def is_evil(n):
    if n==0:
        return True
    else:
        return sum(Integer(n).digits(base=2))%2==0
def remain_evil(n):
    if not(is_evil(n)):
        return False
    else:
        L=Integer(n).digits(base=10)
        M=[]
        for i in [0..len(L)-1]:
            G=L[0:i]+L[i+1:]
            M.append(is_evil(sum(G[i]*10^i for i in [0..len(G)-1])))
        return sum(M)==len(M)
[x for x in [0..500] if remain_evil(x)] # Tom Edgar, Oct 10 2014

Extensions

More terms from Peter J. C. Moses, Oct 10 2014
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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