A JavaScript library that handles arithmetic for numbers as large as {10,9e15,1,1,1,2}.
This reaches level fω3+1.
Some codes snippet from ExpantaNum.js by Naruyoko
Functions are as follows abs, neg, add, sub, mul, div, rec, pow, exp, sqrt, cbrt, root, log10, logarithm, logBase, f_lambertw, d_lambertw, lambertw, tetrate, expansion(eps), multiExpansion(mulEps), powerExpansion(powEps), explosion(els), cmp, isFinite, isInfinite, isNaN, iteratedlog, iteratedslog, iteratedexp, pentate, arrow(some missing items that have not been fully developed)