úθ Ð     !Copyright (c) 2018 Vanessa McHaleNone?The n.th Catalan number, with indexing beginning at 0. See  /http://mathworld.wolfram.com/CatalanNumber.htmlhere. 9»:> mapM catalan [0..9] [1,1,2,5,14,42,132,429,1430,4862]See  5http://mathworld.wolfram.com/BinomialCoefficient.htmlhere.See  1http://mathworld.wolfram.com/DoubleFactorial.htmlhere.Safe—!Copyright (c) 2018 Vanessa McHaleNoneàIndexed starting at 0.O("n)!Copyright (c) 2018 Vanessa McHaleNone See /http://mathworld.wolfram.com/PerfectNumber.htmlhereSum of proper divisors. Number of distinct divisors. %Euler totient function. Experimental.  Safe ² See  -http://mathworld.wolfram.com/Derangement.htmlhere. V»:> fmap derangement [0..10] :: [Integer] [1,0,1,2,9,44,265,1854,14833,133496,1334961]       .fast-arithmetic-0.3.2.6-K8y01RdnUr89urwpFyiICFNumeric.CombinatoricsNumeric.IntegerNumeric.NumberTheory Numeric.PureNumeric.Commoncatalanchoose factorialdoubleFactorial fibonacciisPrime isPerfect sumDivisors littleOmegatautotient derangement hsIsPrime hsFibonacciasTest conjugate