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.

Showing 1-4 of 4 results.

A067403 Third column of triangle A067402.

Original entry on oeis.org

1, 5, 45, 405, 3645, 32805, 295245, 2657205, 23914845, 215233605, 1937102445, 17433922005, 156905298045, 1412147682405, 12709329141645, 114383962274805, 1029455660473245, 9265100944259205, 83385908498332845, 750473176484995605, 6754258588364960445, 60788327295284644005
Offset: 0

Views

Author

Wolfdieter Lang, Jan 25 2002

Keywords

Crossrefs

Cf. A002001 (second column), A067404 (fourth column), A001019 (powers of 9).
Cf. A067402.

Programs

  • Maple
    A067403:=n->5*9^(n-1): 1,seq(A067403(n), n=1..30); # Wesley Ivan Hurt, Apr 09 2017
  • Mathematica
    Join[{1},NestList[9#&,5,30]] (* or *) CoefficientList[Series[ (1-4x)/ (1-9x),{x,0,30}],x] (* Harvey P. Dale, Apr 26 2011 *)
  • PARI
    Vec((1-4*x)/(1-9*x) + O(x^30)) \\ Michel Marcus, Apr 09 2017

Formula

a(n) = A067402(n+2, 2).
a(n) = 5*9^(n-1) for n>=1, a(0) = 1.
G.f.: (1-4*x)/(1-9*x).
E.g.f.: (4 + 5*exp(9*x))/9. - Stefano Spezia, Sep 30 2022

A067425 Triangle with columns built from certain power sequences.

Original entry on oeis.org

1, 4, 1, 16, 5, 1, 64, 40, 6, 1, 256, 320, 72, 7, 1, 1024, 2560, 864, 112, 8, 1, 4096, 20480, 10368, 1792, 160, 9, 1, 16384, 163840, 124416, 28672, 3200, 216, 10, 1, 65536, 1310720, 1492992, 458752, 64000
Offset: 0

Views

Author

Wolfdieter Lang, Jan 25 2002

Keywords

Comments

The fifth column (m=4) gives [1, 8, 160, 3200, 64000, 1280000, 25600000, ...].

Examples

			Triangle starts:
   1;
   4,  1;
  16,  5,  1;
  64, 40,  6,  1;
  ...
		

Crossrefs

Columns 0..3 are A000302 (powers of 4), A067412, A067419, A067404.
Columns 5..8 are A067426, A067427, A067428, A067429.

Programs

  • Mathematica
    A067425[n_, m_] := If[n == m, 1, (m + 4)*(4*(m + 1))^(n - m - 1)];
    Table[A067425[n, m], {n, 0, 10}, {m, 0, n}] (* Paolo Xausa, Oct 16 2024 *)

Formula

T(n,m) = 1 if n = m; T(n,m) = (m+4)*(4*(m+1))^(n-m-1) if n > m >= 0, else 0.
G.f. for column m: (x^m)*(1-3*m*x)/(1-4*(m+1)*x).

A067426 Sixth column of triangle A067425.

Original entry on oeis.org

1, 9, 216, 5184, 124416, 2985984, 71663616, 1719926784, 41278242816, 990677827584, 23776267862016, 570630428688384, 13695130288521216, 328683126924509184, 7888395046188220416, 189321481108517289984
Offset: 0

Views

Author

Wolfdieter Lang, Jan 25 2002

Keywords

Comments

The fifth column of A067425 gives [1, 8, 160, 3200, 64000, 1280000, 25600000, ...].

Crossrefs

Cf. A009968 (powers of 24), A067404 (fourth column), A067425, A067427 (seventh column).

Programs

Formula

a(n) = A067425(n+5, 5).
a(n) = 9*(4*6)^(n-1), n >= 1, a(0)=1.
G.f.: (1-15*x)/(1-24*x).
E.g.f.: (3*exp(24*x) + 5)/8. - Stefano Spezia, Oct 15 2024

A067405 Fifth column of triangle A067402.

Original entry on oeis.org

1, 9, 225, 5625, 140625, 3515625, 87890625, 2197265625, 54931640625, 1373291015625, 34332275390625, 858306884765625, 21457672119140625, 536441802978515625, 13411045074462890625, 335276126861572265625, 8381903171539306640625, 209547579288482666015625, 5238689482212066650390625
Offset: 0

Views

Author

Wolfdieter Lang, Jan 25 2002

Keywords

Crossrefs

Cf. A067404 (fourth column), A067406 (sixth column), A009969 (powers of 25).
Cf. A067402.

Programs

  • Mathematica
    Join[{1},NestList[25#&,9,20]] (* Harvey P. Dale, Mar 12 2023 *)

Formula

a(n) = A067402(n+4, 4).
a(n) = 9*25^(n-1), n>=1, a(0) = 1.
G.f.: (1-16*x)/(1-25*x).
E.g.f.: (16 + 9*exp(25*x))/25. - Stefano Spezia, Sep 30 2022
Showing 1-4 of 4 results.