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.

A249183 a(n) = row n of triangle A249133, concatenated.

Original entry on oeis.org

1, 111, 11011, 1110111, 110101011, 11100000111, 1101100011011, 111011101110111, 11010101010101011, 1110000000000000111, 110110000000000011011, 11101110000000001110111, 1101010110000000110101011, 111000001110000011100000111, 11011000110110001101100011011
Offset: 0

Views

Author

Reinhard Zumkeller, Nov 14 2014

Keywords

Examples

			.   0:                                  1
.   1:                                 111
.   2:                                11011
.   3:                               1110111
.   4:                              110101011
.   5:                             11100000111
.   6:                            1101100011011
.   7:                           111011101110111
.   8:                          11010101010101011
.   9:                         1110000000000000111
.  10:                        110110000000000011011
.  11:                       11101110000000001110111
.  12:                      1101010110000000110101011
.  13:                     111000001110000011100000111
.  14:                    11011000110110001101100011011
.  15:                   1110111011101110111011101110111
.  16:                  110101010101010101010101010101011
.  17:                 11100000000000000000000000000000111
.  18:                1101100000000000000000000000000011011
.  19:               111011100000000000000000000000001110111
.  20:              11010101100000000000000000000000110101011
.  21:             1110000011100000000000000000000011100000111
.  22:            110110001101100000000000000000001101100011011
.  23:           11101110111011100000000000000000111011101110111
.  24:          1101010101010101100000000000000011010101010101011
.  25:         111000000000000011100000000000001110000000000000111
.  26:        11011000000000001101100000000000110110000000000011011
.  27:       1110111000000000111011100000000011101110000000001110111
.  28:      110101011000000011010101100000001101010110000000110101011
.  29:     11100000111000001110000011100000111000001110000011100000111
.  30:    1101100011011000110110001101100011011000110110001101100011011
.  31:   111011101110111011101110111011101110111011101110111011101110111
.  32:  11010101010101010101010101010101010101010101010101010101010101011 .
		

Crossrefs

Cf. A249133, A249184 (decimal), A007088, A006943.

Programs

  • Haskell
    a249183 = foldr (\b v -> 10 * v + b) 0 . a249133_row
  • Mathematica
    a[n_] := FromDigits[Mod[Riffle[Binomial[n, Range[0, n]], Binomial[n - 1, Range[0, n - 1]]], 2]]; Array[a, 15, 0] (* Amiram Eldar, Jul 28 2023 *)

Formula

a(n) = Sum_{k=0..2*n} A249133(n,k)*10^k.
a(n) = A007088(A249184(n));
A055641(a(n)) = A249304(n).