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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A193630 Augmentation of the triangle A074909. See Comments.

Original entry on oeis.org

1, 1, 2, 1, 5, 7, 1, 9, 28, 33, 1, 14, 74, 181, 191, 1, 20, 159, 637, 1333, 1297, 1, 27, 300, 1767, 5906, 11029, 10063, 1, 35, 517, 4190, 20256, 59324, 101351, 87669, 1, 44, 833, 8873, 58339, 244125, 645146, 1024949, 847015, 1, 54, 1274, 17241, 147680
Offset: 0

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Author

Clark Kimberling, Aug 01 2011

Keywords

Comments

For an introduction to the unary operation "augmentation" as applied to triangular arrays or sequences of polynomials, see A193091.
Regarding A193630, writing the general term as w(n,k),
w(n,n): A104981
w(n,n-1): A156629

Examples

			First five rows of A193607:
1
1...2
1...5....7
1...9....28...33
1...14...74...181...191
		

Crossrefs

Programs

  • Mathematica
    p[n_, k_] := Binomial[n + 1, k];
    Table[p[n, k], {n, 0, 7}, {k, 0, n}]  (* A074909 *)
    m[n_] := Table[If[i <= j, p[n + 1 - i, j - i], 0], {i, n}, {j, n + 1}]
    TableForm[m[4]]
    w[0, 0] = 1; w[1, 0] = p[1, 0]; w[1, 1] = p[1, 1];
    v[0] = w[0, 0]; v[1] = {w[1, 0], w[1, 1]};
    v[n_] := v[n - 1].m[n]
    TableForm[Table[v[n], {n, 0, 6}]] (* A193630 *)
    Flatten[Table[v[n], {n, 0, 8}]]
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