238 (number)
238 (two hundred [and] thirty-eight) is the natural number following 237 and preceding 239.
In mathematics
{{Infobox number
| number = 238
| prime = no
}}
238 is an untouchable number.{{Cite OEIS|A005114|name=Untouchable numbers: impossible values for sum of aliquot parts of n}}
There are 238 2-vertex-connected graphs on five labeled vertices,{{Cite OEIS|A013922|name=Number of labeled connected graphs with n nodes and 0 cutpoints (blocks or nonseparable graphs)}} and 238 order-5 polydiamonds (polyiamonds that can partitioned into 5 diamonds).{{Cite OEIS|A056844|name=Number of polydiamonds: polyominoes made from n diamonds}} Out of the 720 permutations of six elements, exactly 238 of them have a unique longest increasing subsequence.{{Cite OEIS|A167995|name=Total number of permutations on {1,2,...,n} that have a unique longest increasing subsequence}}
There are 238 compact and paracompact hyperbolic groups of ranks 3 through 10.{{cite journal |last1=Carbone |first1= Lisa |last2=Chung |first2=Sjuvon |last3=Cobbs |first3=Leigh |last4=Mcrae |first4=Robert |last5=Nandi |first5=Debajyoti |last6=Navqi |first6=Yusra |last7=Penta |first7=Diego |date=March 2010 |title=Classification of hyperbolic Dynkin diagrams, root lengths and Weyl group orbits. |url=https://sites.math.rutgers.edu/~sefiroth/HypClass.pdf |journal=Journal of Physics A: Mathematical and Theoretical |volume=43 |issue=15 |pages=30 |doi=10.1088/1751-8113/43/15/155209 |arxiv= 1003.0564 |bibcode= 2010JPhA...43o5209C |mr=2608277 |s2cid=16946456 |access-date=2022-11-01 }}