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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A297628 Seidel's triangle generating A006846 read by rows, T(n,k) for n>=0 and 0<=k<=n.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 5, 7, 7, 1, 20, 34, 41, 41, 1, 137, 253, 335, 376, 376, 1, 1478, 2818, 3905, 4657, 5033, 5033, 1, 22925, 44371, 62999, 77722, 87788, 92821, 92821, 1, 481448, 939970, 1354121, 1705273, 1978703, 2164345, 2257166, 2257166
Offset: 0

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Author

Peter Luschny, Jan 02 2018

Keywords

Examples

			Triangle starts:
0: [1]
1: [1,       1]
2: [1,       2,       2]
3: [1,       5,       7,        7]
4: [1,      20,      34,       41,       41]
5: [1,     137,     253,      335,      376,      376]
6: [1,    1478,    2818,     3905,     4657,     5033,     5033]
7: [1,   22925,   44371,    62999,    77722,    87788,    92821,    92821]
8: [1,  481448,  939970,  1354121,  1705273,  1978703,  2164345,  2257166,  2257166]
		

Crossrefs

T(n,1) = A297629(n).
T(n,n) = A006846(n).
Row sums are A297630.

Programs

  • Julia
    function  A297628Triangle(len::Int)
        A = fill(BigInt(0), len+1); A[1] = 1
        for n in 1:len
            for k in n:-1:2 A[k] += A[k+1] end
            for k in 2: 1:n A[k] += A[k-1] end
            println(A[1:n])
        end
    end
    println(A297628Triangle(9))
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