## FANDOM

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Hypercalc is a Perl program written by Robert Munafo[1] that is designed to manipulate very large numbers by storing them in a notation called "PT vectors", in which $$a \text{PT} b = \underbrace{10^{10^{10^{.^{.^{.^{b}}}}}}}_a$$. "PT" stands for "Powers of Ten".[2] It is licensed under the GNU General Public License, and operates through a terminal interface. The calculator can handle values up to (10^10) PT 1.0e300, or about $$10\uparrow\uparrow10^{10}$$, much higher than most scientific calculators.

The calculator was first programmed on a Palm Pilot, before it was ported to Perl. The upper limit on that platform was smaller, at 32,768 PT 300.

Kenny Chan created an online version[3] by porting the program to JavaScript. The limit of the online program is higher than the Perl version, and it's $$10\uparrow\uparrow(1.7976\times10^{308})$$ or approximately $$10^{308} PT 10^{34}$$.

The method Hypercalc uses to store its large numbers makes it susceptible to the power-tower paradox.