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 1-5 of 5 results.

A257055 a(n) = n*(n + 1)*(n^2 - n + 3)/6.

Original entry on oeis.org

0, 1, 5, 18, 50, 115, 231, 420, 708, 1125, 1705, 2486, 3510, 4823, 6475, 8520, 11016, 14025, 17613, 21850, 26810, 32571, 39215, 46828, 55500, 65325, 76401, 88830, 102718, 118175, 135315, 154256, 175120, 198033, 223125, 250530, 280386, 312835, 348023, 386100
Offset: 0

Views

Author

Bruno Berselli, Apr 15 2015

Keywords

Comments

Partial sums of A037235.
After 0, this sequence is the 2nd diagonal of the square array in A080851.
For n > 2, a(n)-n is the 4th column of the triangular array in A208657.

Crossrefs

Cf. similar sequences listed in A256859.

Programs

  • Magma
    [n*(n+1)*(n^2-n+3)/6: n in [0..40]];
    
  • Mathematica
    Table[n (n + 1) (n^2 - n + 3)/6, {n, 40}]
  • PARI
    vector(40, n, n--; n*(n+1)*(n^2-n+3)/6)
    
  • Sage
    [n*(n+1)*(n^2-n+3)/6 for n in (0..40)]

Formula

G.f.: x*(1 + 3*x^2)/(1 - x)^5.
a(n) = 3*A000332(n+1) + A000332(n+3).
a(n) = 5*a(n-1)-10*a(n-2)+10*a(n-3)-5*a(n-4)+a(n-5). - Wesley Ivan Hurt, May 27 2021

A261721 Fourth-dimensional figurate numbers.

Original entry on oeis.org

1, 1, 5, 1, 6, 15, 1, 7, 20, 35, 1, 8, 25, 50, 70, 1, 9, 30, 65, 105, 126, 1, 10, 35, 80, 140, 196, 210, 1, 11, 40, 95, 175, 266, 336, 330, 1, 12, 45, 110, 210, 336, 462, 540, 495, 1, 13, 50, 125, 245, 406, 588, 750, 825, 715, 1, 14, 55, 140, 280, 476, 714, 960, 1155, 1210, 1001, 1
Offset: 1

Views

Author

Gary W. Adamson, Aug 30 2015

Keywords

Comments

Generating polygons for the sequences are: Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, ... .
n-th row sequence is the binomial transform of the fourth row of Pascal's triangle (1,n) followed by zeros; and the fourth partial sum of (1, n, n, n, ...).
n-th row sequence is the binomial transform of:
((n-1) * (0, 1, 3, 3, 1, 0, 0, 0) + (1, 4, 6, 4, 1, 0, 0, 0)).
Given the n-th row of the array (1, b, c, d, ...), the next row of the array is (1, b, c, d, ...) + (0, 1, 5, 15, 35, ...)

Examples

			The array as shown in A257200:
  1,  5, 15,  35,  70, 126, 210,  330, ... A000332
  1,  6, 20,  50, 105, 196, 336,  540, ... A002415
  1,  7, 25,  65, 140, 266, 462,  750, ... A001296
  1,  8, 30,  80, 175, 336, 588,  960, ... A002417
  1,  9, 35,  95, 210, 406, 714, 1170, ... A002418
  1, 10, 40, 110, 245, 476, 840, 1380, ... A002419
  ...
(1, 7, 25, 65, 140, ...) is the third row of the array and is the binomial transform of the fourth row of Pascal's triangle (1,3) followed by zeros: (1, 6, 12, 10, 3, 0, 0, 0, ...); and the fourth partial sum of (1, 3, 3, 3, 0, 0, 0).
(1, 7, 25, 65, 140, ...) is the third row of the array and is the binomial transform of: (2 * (0, 1, 3, 3, 1, 0, 0, 0, ...) + (1, 4, 6, 4, 1, 0, 0, 0, ...)); that is, the binomial transform of (1, 6, 12, 10, 3, 0, 0, 0, ...).
Row 2 of the array is (1, 5, 15, 35, 70, ...) + (0, 1, 5, 15, 35, ...), = (1, 6, 20, 50, 105, ...).
		

References

  • Albert H. Beiler, "Recreations in the Theory of Numbers"; Dover, 1966, p. 195 (Table 80).

Crossrefs

Cf. A257200, A261720 (pyramidal numbers), A000332, A002415, A001296, A002417, A002418, A002419.
Similar to A080852 but without row n=0.
Main diagonal gives A256859.

Programs

  • Maple
    A:= (n, k)-> binomial(k+3, 3) + n*binomial(k+3, 4):
    seq(seq(A(d-k, k), k=0..d-1), d=1..13);  # Alois P. Heinz, Aug 31 2015
  • Mathematica
    row[1] = LinearRecurrence[{5, -10, 10, -5, 1}, {1, 5, 15, 35, 70}, m = 10];
    row1 = Join[{0}, row[1] // Most]; row[n_] := row[n] = row[n-1] + row1;
    Table[row[n-k+1][[k]], {n, 1, m}, {k, 1, n}] // Flatten (* Jean-François Alcover, May 26 2016 *)
  • PARI
    A(n, k) = binomial(k+3, 3) + n*binomial(k+3, 4)
    table(n, k) = for(x=1, n, for(y=0, k-1, print1(A(x, y), ", ")); print(""))
    /* Print initial 6 rows and 8 columns as follows: */
    table(6, 8) \\ Felix Fröhlich, Jul 28 2016

Formula

G.f. for row n: (1 + (n-1)*x)/(1 - x)^5.
A(n,k) = C(k+3,3) + n * C(k+3,4) = A080852(n,k).
E.g.f. as array: exp(y)*(exp(x)*(24 + 24*(3 + x)*y + 36*(1 + x)*y^2 + 4*(1 + 3*x)*y^3 + x*y^4) - 4*(6 + 18*y + 9*y^2 + y^3))/24. - Stefano Spezia, Aug 15 2024

A256860 a(n) = n*(n + 1)*(n + 2)*(n + 3)*(n^2 - n + 5)/120.

Original entry on oeis.org

1, 7, 33, 119, 350, 882, 1974, 4026, 7623, 13585, 23023, 37401, 58604, 89012, 131580, 189924, 268413, 372267, 507661, 681835, 903210, 1181510, 1527890, 1955070, 2477475, 3111381, 3875067, 4788973, 5875864, 7161000, 8672312, 10440584, 12499641, 14886543
Offset: 1

Views

Author

Luciano Ancora, Apr 14 2015

Keywords

Comments

This is the case k = n of b(n,k) = n*(n+1)*(n+2)*(n+3)*(k*(n-1)+5)/120, where b(n,k) is the n-th hypersolid number in 5 dimensions generated from an arithmetical progression with the first term 1 and common difference k (see Sardelis et al. paper).

Crossrefs

Cf. A000579.
Cf. similar sequences listed in A256859.

Programs

  • Mathematica
    Table[n (n + 1) (n + 2) (n + 3) (n^2 - n + 5)/120, {n, 40}]
  • PARI
    vector(40, n, n*(n+1)*(n+2)*(n+3)*(n^2-n+5)/120) \\ Bruno Berselli, Apr 15 2015

Formula

G.f.: x*(1 + 5*x^2)/(1 - x)^7.
a(n) = 5*A000579(n+3) + A000579(n+5). [Bruno Berselli, Apr 15 2015]

A256861 a(n) = n*(n + 1)*(n + 2)*(n + 3)*(n + 4)*(n^2 - n + 6)/720.

Original entry on oeis.org

1, 8, 42, 168, 546, 1512, 3696, 8184, 16731, 32032, 58058, 100464, 167076, 268464, 418608, 635664, 942837, 1369368, 1951642, 2734424, 3772230, 5130840, 6888960, 9140040, 11994255, 15580656, 20049498, 25574752, 32356808, 40625376, 50642592, 62706336
Offset: 1

Views

Author

Luciano Ancora, Apr 14 2015

Keywords

Comments

This is the case k = n of b(n,k) = n*(n+1)*(n+2)*(n+3)*(n+4)*(k*(n-1)+6)/120, where b(n,k) is the n-th hypersolid number in 6 dimensions generated from an arithmetical progression with the first term 1 and common difference k (see Sardelis et al. paper).

Crossrefs

Cf. A000580.
Cf. similar sequences listed in A256859.

Programs

  • Mathematica
    Table[n (1 + n) (2 + n) (3 + n) (4 + n) (6 - n + n^2)/720, {n, 40}]
    Table[Times@@(n+Range[0,4])(n^2-n+6)/720,{n,40}] (* or *) LinearRecurrence[ {8,-28,56,-70,56,-28,8,-1},{1,8,42,168,546,1512,3696,8184},40] (* Harvey P. Dale, Sep 25 2019 *)
  • PARI
    vector(40, n, n*(n+1)*(n+2)*(n+3)*(n+4)*(n^2-n+6)/720) \\ Bruno Berselli, Apr 15 2015

Formula

G.f.: x*(1 + 6*x^2)/(1 - x)^8.
a(n) = 6*A000580(n+4) + A000580(n+6). [Bruno Berselli, Apr 15 2015]

A301973 a(n) = (n^2 - 3*n + 6)*binomial(n+2,3)/4.

Original entry on oeis.org

0, 1, 4, 15, 50, 140, 336, 714, 1380, 2475, 4180, 6721, 10374, 15470, 22400, 31620, 43656, 59109, 78660, 103075, 133210, 170016, 214544, 267950, 331500, 406575, 494676, 597429, 716590, 854050, 1011840, 1192136, 1397264, 1629705, 1892100, 2187255, 2518146, 2887924, 3299920, 3757650, 4264820
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 29 2018

Keywords

Comments

For n > 2, a(n) is the n-th term of the partial sums of n-gonal pyramidal numbers (in other words, a(n) is the n-th 4-dimensional n-gonal number).

Crossrefs

Programs

  • Mathematica
    Table[(n^2 - 3 n + 6) Binomial[n + 2, 3]/4, {n, 0, 40}]
    nmax = 40; CoefficientList[Series[x (1 - 2 x + 6 x^2)/(1 - x)^6, {x, 0, nmax}], x]
    nmax = 40; CoefficientList[Series[Exp[x] x (24 + 24 x + 24 x^2 + 10 x^3 + x^4)/24, {x, 0, nmax}], x] Range[0, nmax]!
    Table[SeriesCoefficient[x (1 - 3 x + n x)/(1 - x)^5, {x, 0, n}], {n, 0, 40}]
    LinearRecurrence[{6, -15, 20, -15, 6, -1}, {0, 1, 4, 15, 50, 140}, 41]

Formula

O.g.f.: x*(1 - 2*x + 6*x^2)/(1 - x)^6.
E.g.f.: exp(x)*x*(24 + 24*x + 24*x^2 + 10*x^3 + x^4)/24.
a(n) = [x^n] x*(1 - 3*x + n*x)/(1 - x)^5.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6).
Showing 1-5 of 5 results.