Numeric Series - Solution

by
Erik Oosterwal



  1. Multiply the two digits together then subtract that result from the original number: 92 - (9·2) = 74, 74 - (7·4) = 46, ... 18 - (1·8) = 10
  2. First letter in each positive integer: One, Two, Three, ... Eight, Nine
  3. The first letter of each known planet in our solar system in order from the sun: Mercury, Venus, Earth, ... Neptune, Pluto
  4. Multiply the two digits in each number together to get the next number in the series: 7·7 = 49, 4·9 = 36, ... 1·8 = 8
  5. The second letter of each positive integer: oNe, tWo, tHree, ... tEn, eLeven
  6. Add three to each number to get the next in the series: 8, 11, 14, ... 23, 26
  7. Add 3, then multiply by 2, then add 3, then multiply by 2...: 6, 9, 18, ... 45, 90
  8. Subtract 3, divide by 3, add 3, subtract 3, divide by 3, add 3...: 12, 9, 3, 6, ... 1, 4
  9. Take all but the last digit in each number and raise it to the power of the last digit: 33 = 27, 27 = 128, ... 429981696 = 6.31974818616 x 1045
  10. Triangular numbers: 1, 3, 6, ... 15, 21
  11. Fibonacci numbers: 0, 1, 1, 2, 3, ... 13, 21
  12. Prime numbers: 1, 2, 3, 5, ... 11, 13
  13. I haven't figured this one out yet.



Copyright E. Oosterwal - 2004
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