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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A357012 Triangle read by rows. T(n, k) = [x^k](0^n + 4^n * ((2 - 2*(1 - x)^(1/2)) / x - 1)).

Original entry on oeis.org

1, 0, 1, 0, 4, 2, 0, 16, 8, 5, 0, 64, 32, 20, 14, 0, 256, 128, 80, 56, 42, 0, 1024, 512, 320, 224, 168, 132, 0, 4096, 2048, 1280, 896, 672, 528, 429, 0, 16384, 8192, 5120, 3584, 2688, 2112, 1716, 1430, 0, 65536, 32768, 20480, 14336, 10752, 8448, 6864, 5720, 4862
Offset: 0

Views

Author

Peter Luschny, Sep 09 2022

Keywords

Examples

			[0] 1;
[1] 0,     1;
[2] 0,     4,     2;
[3] 0,    16,     8,     5;
[4] 0,    64,    32,    20,    14;
[5] 0,   256,   128,    80,    56,    42;
[6] 0,  1024,   512,   320,   224,   168,  132;
[7] 0,  4096,  2048,  1280,   896,   672,  528,  429;
[8] 0, 16384,  8192,  5120,  3584,  2688, 2112, 1716, 1430;
[9] 0, 65536, 32768, 20480, 14336, 10752, 8448, 6864, 5720, 4862;
		

Crossrefs

Cf. A000108, A000302, A008549 (row sums), A356651.

Programs

  • Maple
    ogf := n -> 0^n + 4^n * ((2 - 2*(1 - x)^(1/2)) / x - 1):
    ser := n -> series(ogf(n), x, 32):
    seq(lprint([n], seq(coeff(ser(n), x, k), k = 0..n)), n = 0..9);

Formula

T(n, 0) = 0^n, T(n, n) = CatalanNumber(n), otherwise T(n, k) = 4^(n - k)*T(k, k).
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