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.

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A241882 Numbers with d digits that are divisible by 2^d and have at most 2 distinct digits: exactly one even digit and at most one odd digit.

Original entry on oeis.org

2, 4, 6, 8, 12, 16, 32, 36, 44, 52, 56, 72, 76, 88, 92, 96, 112, 144, 232, 272, 336, 344, 544, 552, 616, 656, 696, 744, 776, 888, 944, 992, 1616, 1888, 2112, 2272, 2992, 3232, 3344, 3888, 4144, 4544, 4944, 5552, 5888, 6336, 6656, 7744, 7776, 7888, 9696, 9888
Offset: 1

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Author

J. Lowell, Apr 30 2014

Keywords

Comments

Union of 20 different sequences, all of which are defined as "a(n) contains n digits (either [any odd digit] or [any nonzero even digit] and is divisible by 2^n)."
Subsequence of A050622. - Michel Marcus, May 07 2014

Examples

			24 is not in the sequence because it has distinct even digits.
		

Crossrefs

Cf. A035014, A053312-A053318, A053332-A053338, A053376-A053380 (sequences whose union is this sequence).

Programs

  • PARI
    isok(n) = {digs = digits(n); d = #digs; if (n % 2^d, return (0)); sd = Set(digs); if (#sd > 2, return (0)); if (#sd < 2, return (1)); ((sd[1] % 2) + (sd[2] % 2)) == 1;} \\ Michel Marcus, May 02 2014

Extensions

More terms from Michel Marcus, May 02 2014
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