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.

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A161779 The sequence of factorials convolved with all its regularly "aerated" variants.

Original entry on oeis.org

1, 1, 3, 8, 30, 133, 768, 5221, 41302, 369170, 3677058, 40338310, 483134179, 6271796072, 87709287104, 1314511438945, 21017751750506, 357102350816602, 6424883282375340, 122025874117476166, 2439726373093186274, 51220112287152570828, 1126575412217509969515
Offset: 0

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Author

Gary W. Adamson, Jun 19 2009

Keywords

Comments

Essentially a duplicate of A096161: 1, followed by A096161.
Convolve A000142 = 1,1,2,6,24,... with 1,0,1,0,2,0,6,0,24,.. and with 1,0,0,1,0,0,2,0,0,6,0,0,24,0,0,.. and with 1,0,0,0,1,0,0,0,2,0,0,0,6,... etc.

Examples

			Let the partial products = a, a*b, a*b*c,..., with the first few rows =
(1, 1, 2, 6, 24, 120,...) = a
(1, 1, 3, 7, 28, 128,...) = a*b
(1, 1, 3, 8, 29, 131,...) = a*b*c
(1, 1, 3, 8, 30, 132,...) = a*b*c*d
...converging to A161779
		

Crossrefs

Cf. A096161, row sums of A333144.

Programs

  • Maple
    read("transforms3") ; read("transforms") ; A161779 := proc(N) local a000142,res,n,j ; a000142 := [seq(n!,n=0..N)] ; res := [seq(op(n,a000142),n=1..N)] ; for j from 1 to N do res := CONV( res, AERATE(a000142,j)) ; od: [seq(op(n,res),n=1..N)] end: A161779(30) ; # R. J. Mathar, Jun 23 2009
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0 or i=1, n!,
          add(b(n-i*j, i-1)*j!, j=0..n/i))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..25);  # Alois P. Heinz, Oct 03 2018, revised, Mar 05 2024
  • Mathematica
    b[n_, i_] := b[n, i] = If[i>n, 0, If[Mod[n, i] == 0, (n/i)!, 0] + Sum[j! b[n - i j, i + 1], {j, 0, n/i}]];
    a[n_] := If[n == 0, 1, b[n, 1]];
    a /@ Range[0, 25] (* Jean-François Alcover, Feb 04 2020, after Alois P. Heinz *)

Formula

a(n) = A096161(n) for n >= 1. - R. J. Mathar, Jun 26 2009
a(n) ~ n! * (1 + 1/n^2 + 2/n^3 + 7/n^4 + 28/n^5 + 121/n^6 + 587/n^7 + 3205/n^8 + 19201/n^9 + 123684/n^10), for coefficients see A293266. - Vaclav Kotesovec, Oct 04 2017

Extensions

Extended by R. J. Mathar, Jun 23 2009

A069123 Triangle formed as follows: For n-th row, n >= 0, record the A000041(n) partitions of n; for each partition, write down number of ways to arrange the parts.

Original entry on oeis.org

1, 1, 2, 1, 6, 2, 1, 24, 6, 4, 2, 1, 120, 24, 12, 6, 4, 2, 1, 720, 120, 48, 24, 36, 12, 6, 8, 4, 2, 1, 5040, 720, 240, 120, 144, 48, 24, 36, 24, 12, 6, 8, 4, 2, 1, 40320, 5040, 1440, 720, 720, 240, 120, 576, 144, 96, 48, 24, 72, 36, 24, 12, 6, 16, 8, 4, 2, 1
Offset: 0

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Author

Keywords

Examples

			This is a function of the individual partitions of an integer. For n = 0 to 5 the terms are (1), (1), (2,1), (6,2,1), (24,6,4,2,1). The partitions are ordered with the largest part sizes first, so the row 4 indices are [4], [3,1], [2,2], [2,1,1] and [1,1,1,1].
.
The irregular table starts:
[0] [1]
[1] [1]
[2] [2, 1]
[3] [6, 2, 1]
[4] [24, 6, 4, 2, 1]
[5] [120, 24, 12, 6, 4, 2, 1]
[6] [720, 120, 48, 24, 36, 12, 6, 8, 4, 2, 1]
		

Crossrefs

Using Abramowitz-Stegun ordering of partitions this becomes array A134133.

Programs

  • Mathematica
    Table[Map[Function[n, Apply[Times, n! ]], IntegerPartitions[i]], {i,0,8}] // Flatten (* Geoffrey Critzer, May 19 2009 *)
  • SageMath
    def A069123row(n):
        return [product(factorial(part) for part in partition) for partition in Partitions(n)]
    for n in (0..6): print(A069123row(n)) # Peter Luschny, Apr 10 2020

Formula

[]!=prod_k(n[k]!), or equivalently, []!=prod_k(n[k]!^m[k]).
Showing 1-2 of 2 results.