Multimagic square 36, 100, ... Value for Trimagic squares 1, 50, 675, 4624, ... Similarly the tetramagic sequence 4-Power 0, 1, 16, 81, 256, 625, 1296, ... Sum of 4-Power 0, 1, 17, 98, 354, 979, 2275, ... Sums for Tetramagic squares 0, 1, 177, ... The first known bimagic square has order 8 and magic constant 260 and a bimagic constant of 11180. It has been conjectured by Bensen and Jacoby that no nontrivial bimagic squares of order less than 8 exist. This was shown for magic squares containing the elements 1 to "n" by Boyer and Trump. However, J. R.
81 (number) 81 (number) 81 (eighty-one) is the natural number following 80 and preceding 82. 81 is: The inverse of 81 is 0. recurring, missing only the digit "8" from the complete set of digits. This is an example of the general rule that, in base "b", omitting only the digit "b"−2. Eighty-one is also: The Arabic characters for the numerals 8 and 1 are visible in the left palm of the human hand. In China, 81 always reminds people People's Liberation Army as it was founded on August 1. 81 is used to refer to the motor-club Hell's Angels, since H