cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A291719 Numbers occurring in Ezra Ehrenkrantz's "Modular Coordination System".

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 27, 30, 32, 36, 40, 45, 48, 54, 60, 64, 72, 80, 90, 96, 108, 120, 128, 144, 180, 192, 216, 240, 288, 360, 384, 432, 576, 720, 1152
Offset: 1

Views

Author

Hugo Pfoertner, Aug 30 2017

Keywords

Comments

Cited from Jay Kapraff’s article: "... architect Ezra Ehrenkrantz created a system of architectural proportion that incorporates aspects of Alberti’s and Palladio’s systems made up of lengths factorable by the primes 2, 3, and 5, along with the additive properties of Fibonacci series."

Examples

			The number pattern in three dimensions:
                     A    B     C     D     E
          Plate 3 +---+-----+-----+-----+-----+
                 /|  9   18    36    72   144 |
                / | 18   36    72   144   288 |
               /  | 27   54   108   216   432 |
              /   | 45   90   180   360   720 |
             /    | 72  144   288   576  1152 |
            /     +---+-----+-----+-----+-----+
           / A    B     C     D     E        /
  Plate 2 /---+-----+-----+-----+-----+     /
         /|  3    6    12    24    48 |    /
        / |  6   12    24    48    96 |   /
       /  |  9   18    36    72   144 |  /
      /   | 15   30    60   120   240 | /
     /    | 24   48    96   192   384 |/
    /     +---+-----+-----+-----+-----/
   /  A    B     C     D     E       /
  +---+-----+-----+-----+-----+ Plate 1
  |  1    2     4     8    16 |    /
  |  2    4     8    16    32 |   /
  |  3    6    12    24    48 |  /
  |  5   10    20    40    80 | /
  |  8   16    32    64   128 |/
  +---+-----+-----+-----+-----+
		

References

  • Ezra Ehrenkrantz, Modular Number Pattern, Tiranti, London 1956.

Crossrefs

Programs

  • Maple
    with(combinat):
    {seq(seq(seq(fibonacci(i+2)*2^j*3^k, k=0..2), j=0..4), i=0..4)}[]; # Alois P. Heinz, Aug 30 2017

Formula

Numbers of the form Fibonacci(i+2)*2^j*3^k; i, j=0..4, k=0..2.