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.

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A201634 Triangle read by rows, n>=0, k>=0, T(n,n) = 2^n, T(n,k) = sum_{j=0..k} T(n-1,j) for k=0..n-1.

Original entry on oeis.org

1, 1, 2, 1, 3, 4, 1, 4, 8, 8, 1, 5, 13, 21, 16, 1, 6, 19, 40, 56, 32, 1, 7, 26, 66, 122, 154, 64, 1, 8, 34, 100, 222, 376, 440, 128, 1, 9, 43, 143, 365, 741, 1181, 1309, 256, 1, 10, 53, 196, 561, 1302, 2483, 3792, 4048, 512, 1, 11, 64, 260, 821, 2123, 4606
Offset: 0

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Author

Peter Luschny, Nov 14 2012

Keywords

Comments

Row sums are A014318.

Examples

			[0] [1]
[1] [1, 2]
[2] [1, 3, 4]
[3] [1, 4, 8, 8]
[4] [1, 5, 13, 21, 16]
[5] [1, 6, 19, 40, 56, 32]
[6] [1, 7, 26, 66, 122, 154, 64]
[7] [1, 8, 34, 100, 222, 376, 440, 128]
		

Crossrefs

Cf. A247023 (mirrored).

Programs

  • Haskell
    a201634 n k = a201634_tabl !! n !! k
    a201634_row n = a201634_tabl !! n
    a201634_tabl = iterate (\xs -> scanl1 (+) xs ++ [2 * last xs]) [1]
    -- Reinhard Zumkeller, Sep 20 2014
  • Sage
    @CachedFunction
    def A201634(n, k):
        if k==n: return 2^n
        return add(A201634(n-1, j) for j in (0..k))
    for n in (0..7) : print([A201634(n, k) for k in (0..n)])
    
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