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.

A274622 Irregular triangular array read by rows: coefficients in expansion of Gosper's q-sine function sin_q(Pi*z).

Original entry on oeis.org

1, 1, 2, 2, 1, 4, 4, 1, 2, 8, 8, 2, 4, 14, 14, 4, 8, 24, 24, 8, 1, 14, 40, 40, 14, 1, 2, 24, 64, 64, 24, 2, 4, 40, 100, 100, 40, 4, 8, 64, 154, 154, 64, 8, 14, 100, 232, 232, 100, 14, 24, 154, 344, 344, 154, 24, 1, 40, 232, 504, 504, 232, 40, 1, 2, 64, 344, 728, 728, 344, 64, 2, 4, 100, 504, 1040, 1040, 504, 100, 4
Offset: 0

Views

Author

N. J. A. Sloane, Jul 04 2016

Keywords

Examples

			The array begins:
.........1,1,
.........2,2,
.......1,4,4,1,
.......2,8,8,2,
.......4,14,14,4,
.......8,24,24,8,
....1,14,40,40,14,1,
....2,24,64,64,24,2,
....4,40,100,100,40,4,
....8,64,154,154,64,8,
....14,100,232,232,100,14,
....24,154,344,344,154,24,
..1,40,232,504,504,232,40,1,
..2,64,344,728,728,344,64,2,
..4,100,504,1040,1040,504,100,4,
...
		

References

  • R. W. Gosper, Experiments and discoveries in q-trigonometry, in Symbolic Computation, Number Theory, Special Functions, Physics and Combinatorics. Editors: F. G. Garvan and M. E. H. Ismail. Kluwer, Dordrecht, Netherlands, 2001, pp. 79-105.

Crossrefs

Programs

  • Mathematica
    nmax = 14; kmax = 4; QP = QPochhammer; s = QP[q^2]/QP[q]^2 + O[q]^(nmax + 1); col[1] = CoefficientList [s, q]; col[k_] := Join[Array[0&, k(k-1)], Take[col[1], nmax-k(k-1)+1]]; T = Transpose[Array[col, kmax]]; ro[n_] := DeleteCases[T[[n+1]], 0]; row[n_] := Join[Reverse[ro[n]], ro[n]]; Table[row[n], {n, 0, nmax}] // Flatten (* Jean-François Alcover, Oct 07 2016 *)