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.

A213844 Rectangular array: (row n) = b**c, where b(h) = 2*h-1, c(h) = 4*n-5+4*h, n>=1, h>=1, and ** = convolution.

Original entry on oeis.org

3, 16, 7, 47, 32, 11, 104, 83, 48, 15, 195, 168, 119, 64, 19, 328, 295, 232, 155, 80, 23, 511, 472, 395, 296, 191, 96, 27, 752, 707, 616, 495, 360, 227, 112, 31, 1059, 1008, 903, 760, 595, 424, 263, 128, 35, 1440, 1383, 1264
Offset: 1

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Author

Clark Kimberling, Jul 05 2012

Keywords

Comments

Principal diagonal: A213845.
Antidiagonal sums: A213846.
Row 1, (1,3,5,7...)**(3,7,11,15,...): A172482.
Row 2, (1,3,5,7,...)**(7,11,15,19,...): (4*k^3 + 15*k^2 + 2*k)/3.
Row 3, (1,3,5,7,...)**(11,15,19,23,...): (4*k^3 + 27*k^2 + 2*k)/3.
For a guide to related arrays, see A212500.

Examples

			Northwest corner (the array is read by falling antidiagonals):
3....16...47....104...195...328
7....32...83....168...295...472
11...48...119...232...395...616
15...64...155...296...495...760
		

Crossrefs

Cf. A212500.

Programs

  • Mathematica
    b[n_]:=2n-1;c[n_]:=4n-1;
    t[n_,k_]:=Sum[b[k-i]c[n+i],{i,0,k-1}]
    TableForm[Table[t[n,k],{n,1,10},{k,1,10}]]
    Flatten[Table[t[n-k+1,k],{n,12},{k,n,1,-1}]]
    r[n_]:=Table[t[n,k],{k,1,60}] (* A213844 *)
    Table[t[n,n],{n,1,40}] (* A213845 *)
    s[n_]:=Sum[t[i,n+1-i],{i,1,n}]
    Table[s[n],{n,1,50}] (* A213846 *)

Formula

T(n,k) = 4*T(n,k-1)-6*T(n,k-2)+4*T(n,k-3)-T(n,k-4).
G.f. for row n: f(x)/g(x), where f(x) = x*(4*n-1 + 4*x - (4*n-5)*x^2) and g(x) = (1-x)^4.