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.

Previous Showing 11-13 of 13 results.

A024209 Number of terms in n-th derivative of a function composed with itself 9 times.

Original entry on oeis.org

1, 1, 9, 45, 201, 735, 2517, 7785, 22857, 63024, 166819, 422537, 1035971, 2456694, 5672347, 12756334, 28053280, 60371967, 127479247, 264311585, 539102751, 1082474167, 2142579168, 4183251750, 8064722973, 15360809911, 28928858208, 53896616704, 99398216733
Offset: 0

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Author

Winston C. Yang (yang(AT)math.wisc.edu)

Keywords

References

  • W. C. Yang (yang(AT)math.wisc.edu), Derivatives of self-compositions of functions, preprint, 1997.

Crossrefs

Cf. A008778, A022811-A022817, A024207-A024210. First column of A050303.
Column k=9 of A022818.

Programs

  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[nJean-François Alcover, Apr 28 2017, after Alois P. Heinz *)

Formula

If a(n,m) = number of terms in m-derivative of a function composed with itself n times, p(n,k) = number of partitions of n into k parts, then a(n,m) = sum_{i=0..m} p(m,i)*a(n-1,i).

A022816 Number of terms in 6th derivative of a function composed with itself n times.

Original entry on oeis.org

1, 11, 44, 121, 271, 532, 952, 1590, 2517, 3817, 5588, 7943, 11011, 14938, 19888, 26044, 33609, 42807, 53884, 67109, 82775, 101200, 122728, 147730, 176605, 209781, 247716, 290899, 339851, 395126, 457312, 527032, 604945, 691747
Offset: 1

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Author

Keywords

References

  • W. C. Yang (yang(AT)math.wisc.edu), Derivatives of self-compositions of functions, preprint, 1997.

Crossrefs

Programs

  • Magma
    [n*(n+1)*(n^3+24*n^2+81*n-46)/120: n in [1..40]]; // Vincenzo Librandi, Oct 10 2011
    
  • Mathematica
    Table[n(n+1)(n^3+24n^2+81n-46)/120,{n,40}] (* or *) LinearRecurrence[{6,-15,20,-15,6,-1},{1,11,44,121,271,532},40] (* Harvey P. Dale, Dec 29 2017 *)
  • PARI
    a(n)=n*(n+1)*(n^3+24*n^2+81*n-46)/120 \\ Charles R Greathouse IV, Oct 21 2022

Formula

a(n) = n*(n+1)*(n^3+24*n^2+81*n-46)/120. G.f.: x*(1+5*x-7*x^2+2*x^3)/(x-1)^6. - R. J. Mathar, Sep 15 2009

Extensions

More terms from Christian G. Bower, Aug 15 1999.

A050301 Matrix 7th power of partition triangle A008284.

Original entry on oeis.org

1, 7, 1, 28, 7, 1, 105, 35, 7, 1, 322, 133, 35, 7, 1, 952, 455, 140, 35, 7, 1, 2541, 1379, 483, 140, 35, 7, 1, 6539, 3920, 1512, 490, 140, 35, 7, 1, 15833, 10375, 4354, 1540, 490, 140, 35, 7, 1, 37148, 26243, 11803, 4487, 1547, 490, 140, 35, 7, 1, 83594
Offset: 1

Views

Author

Christian G. Bower, Aug 15 1999

Keywords

Examples

			1; 7,1; 28,7,1; 105,35,7,1; ...
		

Crossrefs

Cf. A038497, A038498, A039805-A039807. A050300-A050304. a(n, 1) = A024207(n) (first column).
Previous Showing 11-13 of 13 results.