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.

A046900 Triangle inverse to that in A046899.

Original entry on oeis.org

1, -1, 1, 1, -3, 2, 1, 3, -10, 6, -1, 9, 10, -42, 24, -17, 21, 50, 42, -216, 120, -107, -33, 230, 294, 216, -1320, 720, -415, -1173, 670, 1974, 1944, 1320, -9360, 5040, 1231, -13515, -4510, 11130, 17064, 14520, 9360, -75600, 40320, 56671, -113739, -131230, 20202, 136296, 157080, 121680, 75600
Offset: 0

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Comments

Sequence gives numerators; denominators are A001813.

Examples

			1; -1/2 1/2; 1/12 -3/12 2/12; ...
		

References

  • H. W. Gould, A class of binomial sums and a series transform, Utilitas Math., 45 (1994), 71-83.

Crossrefs

Programs

  • Maple
    with(linalg): b:=proc(n,k) if k<=n then binomial(n+k,k) else 0 fi end: bb:=(n,k)->b(n-1,k-1): B:=matrix(12,12,bb): A:=inverse(B): a:=(n,k)->((2*n-2)!/(n-1)!)*A[n,k]: for n from 0 to 10 do seq(a(n,k),k=1..n) od; # yields sequence in triangular form - Emeric Deutsch
  • Mathematica
    max = 10; b[n_, k_] := If[k <= n, Binomial[n+k, k], 0]; BB = Table[b[n, k], {n, 0, max-1}, {k, 0, max-1}]; AA = Inverse[BB]; a[n_, k_] := ((2n-2)!/(n-1)!)*AA[[n, k]]; Flatten[ Table[ a[n, k], {n, 1, max}, {k, 1, n}]] (* Jean-François Alcover, Aug 08 2012, after Emeric Deutsch *)

Extensions

More terms from Emeric Deutsch, Jun 25 2005