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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A064999 Partial sums of sequence (essentially A002378): 1, 2, 6, 12, 20, 30, 42, 56, 72, 90, ...

Original entry on oeis.org

1, 3, 9, 21, 41, 71, 113, 169, 241, 331, 441, 573, 729, 911, 1121, 1361, 1633, 1939, 2281, 2661, 3081, 3543, 4049, 4601, 5201, 5851, 6553, 7309, 8121, 8991, 9921, 10913, 11969, 13091, 14281, 15541, 16873, 18279, 19761, 21321, 22961, 24683
Offset: 0

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Author

Klaus E. Kastberg (kastberg(AT)hotkey.net.au), Oct 31 2001

Keywords

Comments

Equals triangle A144328 * [1, 2, 3, ...]. - Gary W. Adamson, Sep 18 2008
a(n) is the number of parking functions of size n+1 avoiding the patterns 123 and 312. - Lara Pudwell, Apr 10 2023

Crossrefs

Cf. A144328. - Gary W. Adamson, Sep 18 2008

Programs

  • Magma
    [(n^3+3*n^2+2*n+3)/3: n in [0..50]]; // Vincenzo Librandi, Feb 28 2016
  • Maple
    a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=a[n-1]+n^2-n od: seq(a[n], n=0..42); # Zerinvary Lajos, Jun 05 2008
  • Mathematica
    Table[(x^3 - x + 3)/3, {x, 1, 100}] (* Artur Jasinski, Feb 14 2007 *)
    LinearRecurrence[{4, -6, 4, -1}, {1, 3, 9, 21}, 50] (* Vincenzo Librandi, Feb 28 2016 *)
  • PARI
    { for (n=0, 1000, if (n, a+=n*(n + 1), a=1); write("b064999.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 03 2009
    
  • PARI
    a(n) = (n^3+3*n^2+2*n+3)/3; \\ Altug Alkan, May 16 2018
    

Formula

a(n) = A007290(n+2) + 1 = (n^3 + 3*n^2 + 2*n + 3)/3.
a(0) = 1, a(n) = n*(n+1) + a(n-1) for n > 1. - Gerald McGarvey, Sep 26 2004
O.g.f.: (1 - x + 3x^2 - x^3)/(1 - x)^4.

Extensions

Corrected and extended by Larry Reeves (larryr(AT)acm.org), Nov 12 2001

A176484 Triangle t(n,m) read by rows: t(n,n)= 1, t(n,m) = (-1)^(n+m)*(m+1), 0<=m

Original entry on oeis.org

1, -1, 1, 1, -2, 1, -1, 2, -3, 1, 1, -2, 3, -4, 1, -1, 2, -3, 4, -5, 1, 1, -2, 3, -4, 5, -6, 1, -1, 2, -3, 4, -5, 6, -7, 1, 1, -2, 3, -4, 5, -6, 7, -8, 1, -1, 2, -3, 4, -5, 6, -7, 8, -9, 1, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 1
Offset: 0

Views

Author

Roger L. Bagula, Apr 18 2010

Keywords

Comments

Row sums are 1, 0, 0, -1, -1, -2, -2, -3, -3, -4, -4,..
Obtained from A144328 by deleting the first column, adding a diagonal of +1's, and multiplication with (-1)^(n-m).

Examples

			1;
-1, 1;
1, -2, 1;
-1, 2, -3, 1;
1, -2, 3, -4, 1;
-1, 2, -3, 4, -5, 1;
1, -2, 3, -4, 5, -6, 1;
-1, 2, -3, 4, -5, 6, -7, 1;
1, -2, 3, -4, 5, -6, 7, -8, 1;
-1, 2, -3, 4, -5, 6, -7, 8, -9, 1;
1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 1;
		

Programs

  • Mathematica
    p[x, 0] = 1;
    p[x_, n_] := p[x, n] = x^n - Sum[(-1)^(i + Mod[n, 2])*i*x^(i - 1), {i, 1, n}];
    Table[CoefficientList[p[x, n], x], {n, 0, 10}];
    Flatten[%]

Formula

t(n,m) = [x^m] (x^n - sum_{j=1..n} (-1)^(j+(n mod 2)) *j*x^(j-1) ) .

A178702 Coefficients of the sum 1+ x/(1-x) + x^2/(1-x^2) + x^3/ ( (1-x)(1-x^2)) + x^4/ ( (1-x)(1-x^3) ) + x^5/ ( (1-x)(1-x^4) ) + x^5 /((1-x^2)(1-x^3)) + x^6/ ( (1-x)(1-x^2)(1-x^3)) + ...

Original entry on oeis.org

1, 1, 2, 2, 4, 6, 7, 10, 14, 20, 24, 32, 40, 54, 69, 86, 106, 135, 165, 206, 256, 311, 378, 460, 555, 670, 808, 970, 1156, 1380, 1638, 1938, 2296, 2706, 3188, 3752, 4390, 5136, 6000, 6990, 8128, 9444, 10944, 12672, 14659, 16904, 19476, 22420, 25753, 29550, 33873, 38759, 44306
Offset: 0

Views

Author

David S. Newman, Dec 27 2010

Keywords

Comments

For a given positive integer, n, let S_n be the set of partitions of n into distinct parts where the number of parts is maximal for that n. For example, for n=6, the set S_6 consists of just one such partition S_6={1,2,3}. Similarly, for n=7, S_7={1,2,4}, But for n=8, S_8 will contain two partitions S_8= { {1,2,5}, {1,3,4} }. Now form the sum whose general term is x^n divided by the product (1-x^(p_1))...(1-x^(p_i)) where the p's come from the partitions in S_n. The sequence is the sequence of coefficients of this sum.
This sequence is an upper bound for A098859.
The initial values of the sequence were verified by several members of the Sequence Fans mailing list.
|S_n| = A144328(n) (if the offset of the latter is changed to 0). - Benoit Jubin, Dec 13 2010.

Crossrefs

Programs

  • Mathematica
    <
    				

Extensions

More terms from Alois P. Heinz, Jun 25 2011
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