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User:Michal Paulovic

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  • AIRMORUT / SPAIUT : Active Independent Recreational Mathematics Occasional Researcher / Self-Proclaimed Amateur Inventor *
  • Chemical engineer, electrician and an amateur geometrician (I do have a degree in mathematics, but I do not do math for money)
  • An avid computer programmer, creating database systems and designing worlds and levels for computer games most of the time
  • Interested in equable shapes, fixed points and near-integers, authored 29 (plus 3 recycled) out of 74 OEIS entries since 2014
  • Almost all contributions are based on the data from my "Constants of Interest" database created and maintained since 2000/2001


Interesting numbers

  • 16 : the perimeter and the area of an equable square with the side length 4, also 42 = 24
  • 18 : the perimeter and the area of an equable rectangle with the side lengths 3 and 6
  • 24 : the perimeter and the area of an equable right triangle with the side lengths 6, 8 and 10
  • 30 : the perimeter and the area of an equable right triangle with the side lengths 5, 12 and 13, also 12 + 22 + 32 + 42 = 52 + 5
  • 36 : the perimeter and the area of an equable triangle with the side lengths 9, 10 and 17, also 62 = 13 + 23 + 33 = 43 -28
  • 42 : the perimeter and the area of an equable triangle with the side lengths 7, 15 and 20
  • 45 : the perimeter and the area of an equable right triangle with the side lengths 4.5, 20 and 20.5, also 47 - 2 = 43 + 2 = 87 - 23 - 19
  • 60 : the perimeter and the area of an equable triangle with the side lengths 6, 25 and 29
  • 216 : the surface area and the volume of an equable cube with the side length 6, also the value of Φ(666) and 33 + 43 + 53 = 63
  • 364.5 : the surface area and the volume of an equable rectangular cuboid with its base perimeter (4.5 * 4) equal to its height (18)
  • 384 : the surface area and the volume of an equable right square pyramid with the base side length 12 and the height 8
  • 5000 : (five thousand) the largest heterogrammic numeral in the English language (all letters in "five thousand" are different)


Favorite expressions

  • e(π * i) + 1 = 0 : Euler's identity, the relation between e, π, i, 1 and 0 by the means of exponentiation, multiplication and addition
  • √5 / 2 + 1/2 = φ : Golden ratio, the ratio of the number of leaves to the number of turns on the stem of a plant with infinite height
  • V - E + F = 2 : Euler's polyhedron formula, the relation between vertices, edges and faces of any convex or spherical polyhedron
  • 504 = 29 - 23 = 153 + 351 = 167 + 168 + 169 = 7 * 8 * 9 = 12 * 42 = 21 * 24; DIV in Roman numerals (WONDER in Sklavenreich)
  • The magic square from Dürer's Melancolia I, engraved in 1514, with magic constant (one of the square's eigenvalues) equal to 34


  16  

  3  

  2  

  13  

  5  

  10  

  11  

  8  

  9  

  6  

  7  

  12  

  4  

  15  

  14  

  1  


Nonsense sentences

  • * The very first line (that AIRMOR stuff) is a complete inside joke.
  • UT - Unregistered Trademark; UTKA (stylized as YTKA) means DUCK in Russian.
  • The name of my computer is EULE; computers are like owls -- people think they are wise, but they are utterly stupid.
  • I know science: gravity makes you fall, water makes you wet, and electricity makes you shake (especially when you are wet).
  • You can call it "memorial park" all you want, it is still a cemetery (unless it has a church on its grounds, then it is a graveyard).
  • Memory disorder is funny: sometimes you stumble upon a constant, you check it against the OEIS, and you find it there... along with the information that you are the one who contributed it.


Exercises sans answers

  • Conical pint glass paradox: What is longer, the circumference of the brim of the glass or the height of the glass?
  • Add together mentally: one thousand plus forty plus one thousand plus thirty plus one thousand plus twenty plus one thousand plus ten. What is the result?

     (It is not the last number listed in the "Interesting numbers" above.)

  • A wire forms a circle around Earth's equator, the wire is 40 inches (1 meter) longer than the equatorial circumference of Earth. Can you put a rabbit between the wire and Earth?
  • A pipe with inner bore 2 inches is 47 yards (43 meters) long. How many whole gallons (liters) of water will fit into the pipe?

     (The answers are hidden somewhere in the "Interesting numbers" above.)


Some readings for long winter evenings

  • List of Editors It might come handy to know who is who (requires login to the OEIS Wiki).
  • Note to meself: A constant may have 105 terms + 104 commas + 104 spaces = 313 characters, but any other sequence should have 260 characters.