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.

A371994 Triangle read by rows: Related to the Euler numbers.

Original entry on oeis.org

1, 0, 1, 0, 1, 5, 0, 1, 19, 61, 0, 1, 42, 498, 1385, 0, 1, 74, 1932, 19238, 50521, 0, 1, 115, 5290, 114830, 1057475, 2702765, 0, 1, 165, 11805, 449539, 8949633, 79160457, 199360981, 0, 1, 224, 23016, 1360198, 47306246, 899141244, 7768928932, 19391512145
Offset: 0

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Author

Peter Luschny, Apr 21 2024

Keywords

Comments

Inspired by Philippe Deléham's formula for A371637.

Examples

			Triangle starts:
  [0] [1]
  [1] [0, 1]
  [2] [0, 1,   5]
  [3] [0, 1,  19,    61]
  [4] [0, 1,  42,   498,   1385]
  [5] [0, 1,  74,  1932,  19238,   50521]
  [6] [0, 1, 115,  5290, 114830, 1057475,  2702765]
  [7] [0, 1, 165, 11805, 449539, 8949633, 79160457, 199360981]
		

Crossrefs

Cf. A000364 (main diagonal), A371637, A371765 (row sums), A372001.
Cf. A084938.

Programs

  • SageMath
    # Using function GeneralizedDelehamDelta from A372001.
    def A371994_triangle(dim):
        a = lambda n: n % 2
        b = lambda n: (n + 1)^2
        return GeneralizedDelehamDelta([a, b], dim, False)
    for row in A371994_triangle(8): print(row)

Formula

Triangle T given by [0, 1, 0, 1, 0, 1, 0, 1, ...] DELTA [1, 4, 9, 16, 25, 36, ...] where DELTA is the operator defined by Deléham in A084938.