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  2. Tris(pentafluorophenyl)borane - Wikipedia

    en.wikipedia.org/wiki/Tris(pentafluorophenyl)borane

    Tris (pentafluorophenyl)borane, sometimes referred to as "BCF", is the chemical compound (C6F5)3B. It is a white, volatile solid. The molecule consists of three pentafluorophenyl groups attached in a "paddle-wheel" manner to a central boron atom; the BC3 core is planar. It has been described as the “ideal Lewis acid ” because of its high ...

  3. 1/2 + 1/4 + 1/8 + 1/16 + ⋯ - ⋯ - Wikipedia

    en.wikipedia.org/wiki/1/2_%2B_1/4_%2B_1/8_%2B_1/...

    1/2 + 1/4 + 1/8 + 1/16 + ⋯. First six summands drawn as portions of a square. The geometric series on the real line. In mathematics, the infinite series ⁠ 1 2 ⁠ + ⁠ 1 4 ⁠ + ⁠ 1 8 ⁠ + ⁠ 1 16 ⁠ + ··· is an elementary example of a geometric series that converges absolutely. The sum of the series is 1. In summation notation ...

  4. List of space groups - Wikipedia

    en.wikipedia.org/wiki/List_of_space_groups

    The possible screw axes are: 2 1, 3 1, 3 2, 4 1, 4 2, 4 3, 6 1, 6 2, 6 3, 6 4, and 6 5. Wherever there is both a rotation or screw axis n and a mirror or glide plane m along the same crystallographic direction, they are represented as a fraction or n/m.

  5. Bioconcentration - Wikipedia

    en.wikipedia.org/wiki/Bioconcentration

    Bioconcentration. In aquatic toxicology, bioconcentration is the accumulation of a water-borne chemical substance in an organism exposed to the water. [1][2] There are several ways in which to measure and assess bioaccumulation and bioconcentration. These include: octanol-water partition coefficients (K OW), bioconcentration factors (BCF ...

  6. Mersenne prime - Wikipedia

    en.wikipedia.org/wiki/Mersenne_prime

    That is, and in accordance with Mihăilescu's theorem, the equation 2 m1 = n k has no solutions where m, n, and k are integers with m > 1 and k > 1. The Mersenne number sequence is a member of the family of Lucas sequences. It is U n (3, 2). That is, Mersenne number m n = 3m n-1 - 2m n-2 with m 0 = 0 and m 1 = 1.

  7. The table consisted of 26 unit fraction series of the form 1/n written as sums of other rational numbers. [9] The Akhmim wooden tablet wrote difficult fractions of the form 1/n (specifically, 1/3, 1/7, 1/10, 1/11 and 1/13) in terms of Eye of Horus fractions which were fractions of the form ⁠ 1 / 2 k ⁠ and remainders expressed in terms of a ...

  8. Bell number - Wikipedia

    en.wikipedia.org/wiki/Bell_number

    The permutations that avoid the generalized patterns 12-3, 32-1, 3-21, 1-32, 3-12, 21-3, and 23-1 are also counted by the Bell numbers. [4] The permutations in which every 321 pattern (without restriction on consecutive values) can be extended to a 3241 pattern are also counted by the Bell numbers. [ 5 ]

  9. Longest increasing subsequence - Wikipedia

    en.wikipedia.org/wiki/Longest_increasing_subsequence

    one of the longest increasing subsequences is. 0, 2, 6, 9, 11, 15. This subsequence has length six; the input sequence has no seven-member increasing subsequences. The longest increasing subsequence in this example is not the only solution: for instance, are other increasing subsequences of equal length in the same input sequence.