úÎ Ó    !Copyright (c) 2018 Vanessa McHaleNoneÌ\( !n \) H»:> derangement <$> [0..10] [1,0,1,2,9,44,265,1854,14833,133496,1334961]The n.th Catalan number, with indexing beginning at 0. 8»:> catalan <$> [0..9] [1,1,2,5,14,42,132,429,1430,4862] \binom{n}{k}  n!! Safe, !Copyright (c) 2018 Vanessa McHaleNoneß O(\sqrt(n)) See /http://mathworld.wolfram.com/PerfectNumber.htmlhereSum of proper divisors. Number of distinct prime factors Number of distinct divisors. Euler totient function.        .fast-arithmetic-0.6.0.2-9K7vR3rDCtG6JsA56CB7ekNumeric.CombinatoricsNumeric.NumberTheoryNumeric.Common derangementcatalanchoose factorialdoubleFactorialisPrime isPerfect sumDivisors littleOmegatautotientasTest conjugate