238 (number)

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238 (two hundred [and] thirty-eight) is the natural number following 237 and preceding 239.

In mathematics

← 237 238 239 →
Cardinal two hundred thirty-eight
Ordinal 238th
(two hundred thirty-eighth)
Factorization 2 × 7 × 17
Prime no
Greek numeral ΣΛΗ´
Roman numeral CCXXXVIII, ccxxxviii
Binary 111011102
Ternary 222113
Senary 10346
Octal 3568
Duodecimal 17A12
Hexadecimal EE16

238 is an untouchable number. [1] There are 238 2-vertex-connected graphs on five labeled vertices, [2] and 238 order-5 polydiamonds (polyiamonds that can partitioned into 5 diamonds). [3] Out of the 720 permutations of six elements, exactly 238 of them have a unique longest increasing subsequence. [4]

There are 238 compact and paracompact hyperbolic groups of ranks 3 through 10. [5]

References

  1. ↑ Sloane, N. J. A. (ed.). "SequenceA005114(Untouchable numbers: impossible values for sum of aliquot parts of n)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  2. ↑ Sloane, N. J. A. (ed.). "SequenceA013922(Number of labeled connected graphs with n nodes and 0 cutpoints (blocks or nonseparable graphs))". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  3. ↑ Sloane, N. J. A. (ed.). "SequenceA056844(Number of polydiamonds: polyominoes made from n diamonds)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  4. ↑ Sloane, N. J. A. (ed.). "SequenceA167995(Total number of permutations on {1,2,...,n} that have a unique longest increasing subsequence)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  5. ↑ Carbone, Lisa; Chung, Sjuvon; Cobbs, Leigh; Mcrae, Robert; Nandi, Debajyoti; Navqi, Yusra; Penta, Diego (March 2010). "Classification of hyperbolic Dynkin diagrams, root lengths and Weyl group orbits" (PDF). Journal of Physics A: Mathematical and Theoretical. 43 (15): 30. arXiv: 1003.0564 . Bibcode:2010JPhA...43o5209C. doi:10.1088/1751-8113/43/15/155209. MR   2608277. S2CID   16946456 . Retrieved 2022-11-01.
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