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.

A131817 a(n) = A051340(n) + A130321(n) - A000012(n).

Original entry on oeis.org

1, 2, 2, 4, 2, 3, 8, 4, 2, 4, 16, 8, 4, 2, 5, 32, 16, 8, 4, 2, 6, 64, 32, 16, 8, 4, 2, 7, 128, 64, 32, 16, 8, 4, 2, 8, 256, 128, 64, 32, 16, 8, 4, 2, 9, 512, 256, 128, 64, 32, 16, 8, 4, 2, 10, 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, 11, 2048, 1024, 512, 256, 128, 64, 32, 16, 8, 4, 2, 12
Offset: 0

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Author

Gary W. Adamson, Jul 18 2007

Keywords

Examples

			First few rows of the triangle:
   1;
   2,  2;
   4,  2,  3;
   8,  4,  2,  4;
  16,  8,  4,  2,  5;
  32, 16,  8,  4,  2,  6;
  64, 32, 16,  8,  4,  2,  7;
  ...
		

Crossrefs

Cf. A051340, A083706 (row sums), A130321.

Programs

  • Mathematica
    Array[Append[ConstantArray[1, # - 1], #] + 2^Range[# - 1, 0, -1] - 1 &, 12] // Flatten (* Michael De Vlieger, Aug 19 2021 *)

Formula

A051340 + A130321 - A000012 as infinite lower triangular matrices.

Extensions

More terms from Jinyuan Wang, Aug 19 2021