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.

A288842 Triangle (sans apex) of coefficients of terms of the form (eM_1)^j*(eM_2)^k re construction of triangle A287768.

Original entry on oeis.org

1, 2, 3, 9, 6, 9, 36, 45, 18, 27, 135, 243, 189, 54, 81, 486, 1134, 1296, 729, 162, 243, 1701, 4860, 7290, 6075, 2673, 486, 729, 5832, 19683, 36450, 40095, 26244, 9477, 1458, 2187, 19683, 76545, 168399, 229635, 199017, 107163, 32805, 4374, 6561, 65610, 288684, 734832, 1194102, 1285956, 918540, 419904, 111537, 13122
Offset: 1

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Author

Gregory Gerard Wojnar, Jun 17 2017

Keywords

Examples

			Triangle begins:
  1,  2;
  3,  9,  6;
  9, 36, 45, 18;
		

Crossrefs

Columns are: A000244, A288834, A288835, A288836, A288838, etc.
Cf. A287768.

Programs

  • Mathematica
    T[1, 1] = 1; T[1, 2] = 2;
    T[n_, k_] /; 1 <= k <= n+1 := T[n, k] = 3 T[n-1, k-1] + 3 T[n-1, k];
    T[, ] = 0;
    Table[T[n, k], {n, 1, 9}, {k, 1, n+1}] // Flatten (* Jean-François Alcover, Nov 16 2018 *)

Formula

T(n+1,k+1) = 3*T(n,k) + 3*T(n,k+1).