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 21-27 of 27 results.

A347587 Number of partitions of n into at most 5 distinct parts.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, 22, 27, 32, 38, 46, 54, 64, 75, 88, 102, 119, 137, 158, 181, 207, 235, 268, 302, 341, 383, 430, 480, 536, 595, 661, 731, 808, 889, 979, 1073, 1176, 1285, 1403, 1527, 1662, 1803, 1956, 2116, 2288, 2468, 2662, 2864, 3080, 3306, 3547
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 08 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 58; CoefficientList[Series[Sum[x^(k (k + 1)/2)/Product[(1 - x^j), {j, 1, k}], {k, 0, 5}], {x, 0, nmax}], x]
    LinearRecurrence[{1, 1, 0, 0, -1, -1, -1, 1, 1, 1, 0, 0, -1, -1, 1}, {1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, 22}, 59]

Formula

G.f.: Sum_{k=0..5} x^(k*(k + 1)/2) / Product_{j=1..k} (1 - x^j).

A008766 Expansion of (1+x^5)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 10, 13, 18, 23, 29, 36, 45, 54, 65, 77, 91, 106, 123, 141, 162, 184, 208, 234, 263, 293, 326, 361, 399, 439, 482, 527, 576, 627, 681, 738, 799, 862, 929, 999, 1073, 1150, 1231, 1315, 1404, 1496, 1592, 1692, 1797, 1905, 2018, 2135, 2257, 2383, 2514, 2649, 2790, 2935
Offset: 0

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Author

Keywords

Comments

From Washington Bomfim, Jan 14 2021: (Start)
Let \n,m\ be the number of partitions of n into m non-distinct parts.
For n >= 1, \n,5\ = round((2*n^3-15*n^2+60*n-110*[n mod 2 = 0]-65*[n mod 2])/144).
For n >= 10, \n,5\ = A026811(n) - A026811(n-10).
(End)

Crossrefs

Programs

  • GAP
    a:=[1,1,2,3,5,7,10,13,18];; for n in [10..60] do a[n]:=2*a[n-1]-a[n-2]+a[n-3]-a[n-4]-a[n-5]+a[n-6]-a[n-7]+2*a[n-8]-a[n-9]; od; a; # G. C. Greubel, Sep 10 2019
    
  • Magma
    R:=PowerSeriesRing(Integers(), 60); Coefficients(R!( (1+x^5)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)) )); // G. C. Greubel, Sep 10 2019
    
  • Maple
    seq(coeff(series((1+x^5)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)), x, n+1), x, n), n = 0 .. 60); # G. C. Greubel, Sep 10 2019
  • Mathematica
    CoefficientList[Series[(1+x^5)/(1-x)/(1-x^2)/(1-x^3)/(1-x^4),{x,0,60}],x] (* or *) LinearRecurrence[{2,-1,1,-1,-1,1,-1,2,-1}, {1,1,2,3,5,7,10, 13,18}, 60] (* Harvey P. Dale, Jul 24 2016 *)
  • PARI
    Vec((1+x^5)/(1-x)/(1-x^2)/(1-x^3)/(1-x^4) +O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012
    
  • PARI
    seq(x) = { a = vector(x+1); my(N = 5);
    for(n=0,x, a[n+1]=round((2*N^3-15*N^2+60*N-110*!(N%2)-65*(N%2))/144); N++);a};
    seq(60) \\ Washington Bomfim, Jan 14 2021
  • Sage
    def A008766_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P((1+x^5)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4))).list()
    A008766_list(60) # G. C. Greubel, Sep 10 2019
    

Formula

a(n) = round((2*N^3 - 15*N^2 + 60*N - 110*[N mod 2=0] - 65*[N mod 2])/144), where N = n+5. - Washington Bomfim, Jan 14 2021

Extensions

Terms a(45) onward added by G. C. Greubel, Sep 10 2019

A050910 Number of pure 3-complexes on 8 unlabeled nodes with n multiple 3-simplexes.

Original entry on oeis.org

1, 1, 5, 21, 131, 940, 7902, 69025, 594203, 4856288, 37189863, 265916174, 1778005595, 11154474602, 65921168577, 368463685296, 1955231394323, 9884229508860, 47752849848446, 221109815065563, 983764137502726
Offset: 0

Views

Author

Vladeta Jovovic, Dec 29 1999

Keywords

Crossrefs

Programs

A256525 Number of partitions of 3n into at most 5 parts.

Original entry on oeis.org

1, 3, 10, 23, 47, 84, 141, 221, 333, 480, 674, 918, 1226, 1602, 2062, 2611, 3266, 4033, 4932, 5969, 7166, 8529, 10083, 11835, 13811, 16019, 18487, 21224, 24260, 27604, 31289, 35324, 39744, 44559, 49806, 55496, 61667, 68331, 75529, 83273, 91606, 100540
Offset: 0

Views

Author

Colin Barker, Apr 01 2015

Keywords

Examples

			For n=1 the 3 partitions of 1*3 = 3 are [3], [1,2] and [1,1,1].
		

Crossrefs

Cf. A001401, A077043 (3 parts), A256524 (4 parts), A256315 (6 parts).

Programs

  • Mathematica
    Table[Length[IntegerPartitions[3n,5]],{n,0,50}] (* Harvey P. Dale, Mar 08 2019 *)
  • PARI
    concat(1, vector(40, n, k=0; forpart(p=3*n, k++, , [1,5]); k))
    
  • PARI
    Vec(-(x^8+x^7+4*x^6+5*x^5+5*x^4+5*x^3+4*x^2+x+1) / ((x-1)^5*(x+1)^2*(x^2+1)*(x^4+x^3+x^2+x+1)) + O(x^100))

Formula

G.f.: -(x^8+x^7+4*x^6+5*x^5+5*x^4+5*x^3+4*x^2+x+1) / ((x-1)^5*(x+1)^2*(x^2+1)*(x^4+x^3+x^2+x+1)).
a(n) = A001401(3n). - Alois P. Heinz, Apr 01 2015

A256539 Number of partitions of 4n into at most 5 parts.

Original entry on oeis.org

1, 5, 18, 47, 101, 192, 333, 540, 831, 1226, 1747, 2418, 3266, 4319, 5608, 7166, 9027, 11229, 13811, 16814, 20282, 24260, 28796, 33940, 39744, 46262, 53550, 61667, 70673, 80631, 91606, 103664, 116875, 131310, 147042, 164147, 182702, 202787, 224484, 247877
Offset: 0

Views

Author

Colin Barker, Apr 01 2015

Keywords

Examples

			For n=2 the 18 partitions of 2*4 = 8 are [8], [1,7], [2,6], [3,5], [4,4], [1,1,6], [1,2,5], [1,3,4], [2,2,4], [2,3,3], [1,1,1,5], [1,1,2,4], [1,1,3,3], [1,2,2,3], [2,2,2,2], [1,1,1,1,4], [1,1,1,2,3] and [1,1,2,2,2].
		

Crossrefs

Cf. A001401, A238340 (4 parts), A256540 (6 parts).

Programs

  • PARI
    concat(1, vector(40, n, k=0; forpart(p=4*n, k++, , [1,5]); k))
    
  • PARI
    Vec(-(x^7+4*x^6+5*x^5+7*x^4+6*x^3+6*x^2+2*x+1) / ((x-1)^5*(x^2+x+1)*(x^4+x^3+x^2+x+1)) + O(x^100))

Formula

G.f.: -(x^7+4*x^6+5*x^5+7*x^4+6*x^3+6*x^2+2*x+1) / ((x-1)^5*(x^2+x+1)*(x^4+x^3+x^2+x+1)).
a(n) = A001401(4n). - Alois P. Heinz, Apr 01 2015

A274322 Number of partitions of n^2 into at most five parts.

Original entry on oeis.org

1, 1, 5, 23, 101, 377, 1226, 3507, 9027, 21224, 46262, 94512, 182702, 336666, 595085, 1014091, 1673243, 2682685, 4192118, 6401314, 9572962, 14047457, 20260601, 28763703, 40247228, 55567352, 75776769, 102158957, 136267461, 179969238, 235493851, 305487369
Offset: 0

Views

Author

Colin Barker, Jun 20 2016

Keywords

Crossrefs

A subsequence of A001401.

Programs

  • PARI
    \\ b(n) is the coefficient of x^n in the g.f. 1/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5)).
    b(n) = round(((n+5)^4+10*((n+5)^3+(n+5)^2)-75*(n+5)-45*(n+5)*(-1)^(n+5))/2880)
    vector(40, n, n--; b(n^2))

Formula

Coefficient of x^(n^2) in 1/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5)).
a(n) = A001401(n^2).
Empirical g.f.: (1 -3*x +4*x^2 +13*x^3 +21*x^4 +63*x^5 +138*x^6 +204*x^7 +257*x^8 +280*x^9 +267*x^10 +201*x^11 +128*x^12 +67*x^13 +31*x^14 +6*x^15 +x^16 +x^17) / ((1 -x)^9*(1 +x)^3*(1 +x +x^2)*(1 +x +x^2 +x^3 +x^4)).

A307449 Irregular triangle read by rows: T(n, k) gives the coefficients of the Girard-Waring formula for the sum of n-th power of five indeterminates in terms of their elementary symmetric functions (reverse Abramowitz-Stegun order of partitions).

Original entry on oeis.org

1, 1, -2, 1, -3, 3, 1, -4, 2, 4, -4, 1, -5, 5, 5, -5, -5, 5, 1, -6, 9, 6, -2, -12, -6, 3, 6, 6, 1, -7, 14, 7, -7, -21, -7, 7, 7, 14, 7, -7, -7, 1, -8, 20, 8, -16, -32, -8, 2, 24, 12, 24, 8, -8, -8, -16, -16, 4, 8, 1, -9, 27, 9, -30, -45, -9, 9, 54, 18, 36, 9, -9, -27, -27, -27, -27, 3, 18, 9, 9, 18, -9, 1, -10, 35, 10, -50, -60, -10, 25, 100, 25, 50, 10, -2, -40, -60, -60, -40, -40, 15, 10, 10, 60, 30, 15, 30, -10, -10, -20, -20, 5
Offset: 1

Views

Author

Wolfdieter Lang, May 14 2019

Keywords

Comments

The length of row n is A001401(n), n >= 1.
The Girard-Waring formula for the power sum p(5,n) = Sum_{j=1..5} (x_j)^n in terms of the elementary symmetric functions e_j(x_1, x_2, x_3, x_4), for j = 1, 2 ,..., 5 is given in the W. Lang reference, Theorem 1, in an explicitly nested four sums version. See also the summary link, for N = 5 (there sigma_j^{(N)} -> e_j here).
In this array the partitions of n, with all partitions with a part >= 6 omitted, are used. Here the partitions appear in the reverse Abramowitz-Stegun order. See row n of the array of Waring numbers A115131, read backwards, with the entries corresponding to these omitted partitions.

Examples

			The irregular triangle T(n, k) begins:
n\k 1   2  3  4   5   6  7 8  9 10 11 12 13  14  15  16  17 18 19 20 21 22 23
-----------------------------------------------------------------------------
1:  1
2:  1  -2
3:  1  -3  3
4:  1  -4  2  4  -4
5:  1  -5  5  5  -5  -5  5
6:  1  -6  9  6  -2 -12 -6 3  6  6
7:  1  -7 14  7  -7 -21 -7 7  7 14  7 -7 -7
8:  1  -8 20  8 -16 -32 -8 2 24 12 24  8 -8  -8 -16 -16   4  8
9:  1  -9 27  9 -30 -45 -9 9 54 18 36  9 -9 -27 -27 -27 -27  3 18  9  9 18 -9
.
.
.
n = 10: 1 -10 35 10 -50 -60 -10 25 100 25 50 10 -2 -40 -60 -60 -40 -40 15 10 10 60 30 15 30 -10 -10 -20 -20 5.
...
------------------------------------------------------------------------------
Row n = 6: x_1^6 + x_2^6 + x_3^6 + x_4^6 + x_5^6 =  1*e_1^6  - 6*e_1^4*e_2 + 9*e_1^2*e_2^2 + 6*e_1^3*e_3 - 2*e_2^3 - 12*e_1*e_2*e_3 - 6*e_1^2*e_4 + 3*e_3^2 + 6*e_2*e_4 + 6*e_1*e_5,  with e_1 = Sum_{j=1..5} x_j, e_2 = x1*(x_2 + x_3 + x_4 + x_5) + x_2*(x_3 + x_4 + x_5) + x_3*(x_4 + x_5) + x_4*x_5, e_3 = x_1*x_2*x_3 + x_1*x_2*x_4 +  x_1*x_2*x_5 +  x_2*x_3*x_4 + x_2*x_3*x_5 + x_2*x_4*x_5 + x_3*x_4*x_5, e_4 =  x_1*x_2*x_3*x_4 + x_1*x_2*x_3*x_5 + x_1*x_2*x_4*x_5 + x_1*x_3*x_4*x_5 + x_2*x_3*x_4*x_5, e_5 = Product_{i=1..5} x_j.
		

Crossrefs

Cf. A001401, A115131, A132460 (N=2), A325477 (N=3), A324602 (N=4).

Formula

T(n, k) is the k-th coefficient of the Waring number partition array A115131(n, m) (k there is replaced here by m), read backwards, omitting all partitions which have a part >= 6.
Previous Showing 21-27 of 27 results.