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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A006974 Coefficients of Chebyshev T polynomials: a(n) = A053120(n+8, n), n >= 0.

Original entry on oeis.org

1, 9, 50, 220, 840, 2912, 9408, 28800, 84480, 239360, 658944, 1770496, 4659200, 12042240, 30638080, 76873728, 190513152, 466944000, 1133117440, 2724986880, 6499598336, 15386804224, 36175872000, 84515225600, 196293427200, 453437816832
Offset: 0

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Author

Keywords

Comments

If X_1,X_2,...,X_n are 2-blocks of a (2n+1)-set X then, for n>=3, a(n-3) is the number of (n+4)-subsets of X intersecting each X_i, (i=1,2,...,n). - Milan Janjic, Nov 18 2007
The fourth corrector line for transforming 2^n offset 0 with a leading 1 into the Fibonacci sequence. [Al Hakanson (hawkuu(AT)gmail.com), Jun 01 2009]

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 795.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A039991 (see column 8), A003472 (partial sums), A053120.

Programs

  • Magma
    [2^(n-1)/4*Binomial(n+3,3)*(n+8) : n in [0..25]]; // Brad Clardy, Mar 08 2012
  • Maple
    a := n->n*(n+1)*(n+2)*(n+7)*2^(n-5)/3;

Formula

G.f.: (1-x)/(1-2*x)^5.
a(n) = Sum_{k=0..floor((n+8)/2)} C(n+8, 2k)*C(k, 4). - Paul Barry, May 15 2003
Binomial transform of a(n)=(24*n^4-134*n^3+261*n^2-130*n+3)/3 offset 0. a(3)=220. [Al Hakanson (hawkuu(AT)gmail.com), Jun 01 2009]
a(n) = 2^(n-3)*binomial(n+3, 3)*(n+8). - Brad Clardy, Mar 08 2012 [See a comment in A053120 on subdiagonals. - Wolfdieter Lang, Jan 03 2020]
E.g.f.: (1/3)*exp(2*x)*(3 + 21*x + 27*x^2 + 10*x^3 + x^4). - Stefano Spezia, Aug 17 2019

Extensions

Name clarified by Wolfdieter Lang, Nov 26 2019

A130810 If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 4-subsets of X containing none of X_i, (i=1,...,n).

Original entry on oeis.org

16, 80, 240, 560, 1120, 2016, 3360, 5280, 7920, 11440, 16016, 21840, 29120, 38080, 48960, 62016, 77520, 95760, 117040, 141680, 170016, 202400, 239200, 280800, 327600, 380016, 438480, 503440, 575360, 654720, 742016, 837760, 942480, 1056720
Offset: 4

Views

Author

Milan Janjic, Jul 16 2007

Keywords

Comments

Number of n permutations (n>=4) of 3 objects u,v,z, with repetition allowed, containing n-4 u's. Example: if n=4 then n-4 =(0) zero u, a(1)=16 because we have vvvv zzzz vvvz zzzv vvzv zzvz vzvv zvzz zvvv vzzz vvzz zzvv vzvz zvzv zvvz vzzv. - Zerinvary Lajos, Aug 05 2008
a(n) is the number of 3-dimensional elements in an n-cross polytope where n>=4. - Patrick J. McNab, Jul 06 2015

Crossrefs

Programs

  • Maple
    a:= n-> binomial(2*n,4) +binomial(n,2) -n*binomial(2*n-2,2);
    seq(binomial(n, n-4)*2^4, n=4..37); # Zerinvary Lajos, Dec 07 2007
  • Mathematica
    a[n_] := 16 * Binomial[n, 4]; Array[a, 34, 4] (* Amiram Eldar, Jul 25 2025 *)
  • PARI
    a(n) = 16 * binomial(n, 4); \\ Amiram Eldar, Jul 25 2025

Formula

a(n) = binomial(2*n,4) + binomial(n,2) - n*binomial(2*n-2,2).
a(n) = binomial(n,4)*16. - Zerinvary Lajos, Dec 07 2007
G.f.: 16*x^4/(1-x)^5. - Colin Barker, Apr 14 2012
a(n) = 2*n*(n-1)*(n-2)*(n-3)/3 = 2*A162668(n-3). - Robert Israel, Jul 06 2015
a(n) = 16 * A000332(n). - Alois P. Heinz, Oct 26 2020
E.g.f.: 2*exp(x)*x^4/3. - Stefano Spezia, Jul 17 2025
From Amiram Eldar, Jul 25 2025: (Start)
Sum_{n>=4} 1/a(n) = 1/12.
Sum_{n>=4} (-1)^n/a(n) = 2*log(2) - 4/3. (End)

A162007 Third left hand column of the EG1 triangle A162005.

Original entry on oeis.org

1, 270, 36096, 4766048, 704357760, 120536980224, 24060789342208, 5590122715250688, 1503080384197754880, 464520829174515630080, 163839204411117787938816, 65500849343294249018327040
Offset: 3

Views

Author

Johannes W. Meijer, Jun 27 2009

Keywords

Crossrefs

Third left hand column of the EG1 triangle A162005.
Other left hand columns are A000182 and A162006.
Related to A094665, A083061 and A156919.
A000079, A036289 and A100381 appear in the a(n, 3) formula.
A001789, A003472, A054849, A002409, A054851, A140325 and A140354 (scaled by 2^(m-1)) appear one by one in the a(n, m) formulas for m= 4 and higher .

Programs

  • Maple
    nmax := 14; mmax := nmax: imax := nmax: T1(0, x) := 1: T1(0, x+1) := 1: for i from 1 to imax do T1(i, x) := expand((2*x+1)*(x+1)*T1(i-1, x+1) - 2*x^2*T1(i-1, x)): dx := degree(T1(i, x)): for k from 0 to dx do c(k) := coeff(T1(i, x), x, k) od: T1(i, x+1) := sum(c(j1)*(x+1)^(j1), j1 = 0..dx): od: for i from 0 to imax do for j from 0 to i do A083061(i, j) := coeff(T1(i, x), x, j) od: od: for n from 0 to nmax do for k from 0 to n do A094665(n+1, k+1) := A083061(n, k) od: od: A094665(0, 0) := 1: for n from 1 to nmax do A094665(n, 0) := 0 od: for m from 1 to mmax do A156919(0, m) := 0 end do: for n from 0 to nmax do A156919(n, 0) := 2^n end do: for n from 1 to nmax do for m from 1 to mmax do A156919(n, m) := (2*m+2)*A156919(n-1, m) + (2*n-2*m+1) * A156919(n-1, m-1) end do end do: m:=3; for n from m to nmax do a(n, m) := sum((-1)^(m-p1-1)*sum(2^(n-q-1)*binomial(n-q-1, m-p1-1) * A094665(n-1, q) * A156919(q, p1), q=1..n-m+p1), p1=0..m-1) od: seq(a(n, m), n = m..nmax);
    # Maple program edited by Johannes W. Meijer, Sep 25 2012

Formula

a(n) = sum((-1)^(m-p-1)*sum(2^(n-q-1)*binomial(n-q-1,m-p-1)*A094665(n-1,q)* A156919(q,p),q=1..n-m+p), p=0..m-1) with m = 3.

A130812 If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 6-subsets of X containing none of X_i, (i=1,...n).

Original entry on oeis.org

64, 448, 1792, 5376, 13440, 29568, 59136, 109824, 192192, 320320, 512512, 792064, 1188096, 1736448, 2480640, 3472896, 4775232, 6460608, 8614144, 11334400, 14734720, 18944640, 24111360, 30401280, 38001600, 47121984, 57996288, 70884352, 86073856, 103882240
Offset: 6

Views

Author

Milan Janjic, Jul 16 2007

Keywords

Comments

Number of n permutations (n>=6) of 3 objects u,v,z, with repetition allowed, containing n-6 u's. Example: if n=6 then n-6 =(0) zero u, a(1)=64. - Zerinvary Lajos, Aug 05 2008
a(n) is the number of 5-dimensional elements in an n-cross polytope where n>=6. - Patrick J. McNab, Jul 06 2015

Crossrefs

Programs

  • Magma
    [Binomial(2*n,6)+Binomial(n,2)*Binomial(2*n-4,2)- n*Binomial(2*n-2,4)-Binomial(n,3): n in [6..40]]; // Vincenzo Librandi, Jul 09 2015
  • Maple
    a:=n->binomial(2*n,6)+binomial(n,2)*binomial(2*n-4,2)-n*binomial(2*n-2,4)-binomial(n,3);
    seq(binomial(n,n-6)*2^6,n=6..32); # Zerinvary Lajos, Dec 07 2007
    seq(binomial(n+5, 6)*2^6, n=1..22); # Zerinvary Lajos, Aug 05 2008
  • Mathematica
    CoefficientList[Series[64/(1-x)^7,{x,0,30}],x] (* Vincenzo Librandi, Mar 21 2012 *)

Formula

a(n) = binomial(2*n,6) + binomial(n,2)*binomial(2*n-4,2) - n*binomial(2*n-2,4) - binomial(n,3).
a(n) = C(n,n-6)*2^6, n>=6. - Zerinvary Lajos, Dec 07 2007
G.f.: 64*x^6/(1-x)^7. - Colin Barker, Mar 20 2012

A172242 Number of 10-D hypercubes in an n-dimensional hypercube.

Original entry on oeis.org

1, 22, 264, 2288, 16016, 96096, 512512, 2489344, 11202048, 47297536, 189190144, 722362368, 2648662016, 9372188672, 32133218304, 107110727680, 348109864960, 1105760747520, 3440144547840, 10501493882880, 31504481648640
Offset: 10

Views

Author

Zerinvary Lajos, Jan 29 2010

Keywords

Comments

With a different offset, number of n-permutations (n>=8) of 3 objects: u, v, z with repetition allowed, containing exactly ten (10) u's.

Crossrefs

Programs

  • Mathematica
    Table[Binomial[n + 10, 10]*2^n, {n, 0, 22}]
  • Sage
    [lucas_number2(n, 2, 0)*binomial(n,10)/2^10 for n in range(10, 31)] # Zerinvary Lajos, Feb 05 2010

Formula

a(n) = A038207(n,10).
a(n) = binomial(n,10)*2^(n-10). [Corrected by R. J. Mathar, Feb 21 2010]
G.f.: -x^10/(2*x-1)^11. - Colin Barker, Nov 11 2012
a(n) = Sum_{i=10..n} binomial(i,10)*binomial(n,i). Example: for n=15, a(15) = 1*3003 + 11*1365 + 66*455 + 286*105 + 1001*15 + 3003*1 = 96096. - Bruno Berselli, Mar 23 2018
From Amiram Eldar, Jan 07 2022: (Start)
Sum_{n>=10} 1/a(n) = 1879/126 - 20*log(2).
Sum_{n>=10} (-1)^n/a(n) = 393660*log(3/2) - 20111419/126. (End)

A130811 If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 5-subsets of X containing none of X_i, (i=1,...n).

Original entry on oeis.org

32, 192, 672, 1792, 4032, 8064, 14784, 25344, 41184, 64064, 96096, 139776, 198016, 274176, 372096, 496128, 651168, 842688, 1076768, 1360128, 1700160, 2104960, 2583360, 3144960, 3800160, 4560192, 5437152, 6444032, 7594752, 8904192
Offset: 5

Views

Author

Milan Janjic, Jul 16 2007

Keywords

Comments

Number of n permutations (n>=5) of 3 objects u,v,z, with repetition allowed, containing n-5 u's. Example: if n=5 then n-5 =(0) zero u, a(1)=32. - Zerinvary Lajos, Aug 05 2008
a(n) is the number of 4-dimensional elements in an n-cross polytope where n>=5. - Patrick J. McNab, Jul 06 2015

Crossrefs

Programs

  • Magma
    [Binomial(n,n-5)*2^5: n in [5..40]]; // Vincenzo Librandi, Jul 09 2015
  • Maple
    a:=n->binomial(2*n,5)+(2*n-4)*binomial(n,2)-n*binomial(2*n-2,3)
    seq(binomial(n,n-5)*2^5,n=5..34); # Zerinvary Lajos, Dec 07 2007
    seq(binomial(n+4, 5)*2^5, n=1..22); # Zerinvary Lajos, Aug 05 2008
  • Mathematica
    Table[Binomial[2 n, 5] + (2 n - 4) Binomial[n, 2] - n Binomial[2 n - 2, 3], {n, 5, 40}] (* Vincenzo Librandi, Jul 09 2015 *)

Formula

a(n) = binomial(2*n,5) + (2*n-4)*binomial(n,2) - n*binomial(2*n-2,3).
a(n) = C(n,n-5)*2^5, for n>=5. - Zerinvary Lajos, Dec 07 2007
G.f.: 32*x^5/(1-x)^6. - Colin Barker, Apr 14 2012

A178821 Triangle read by rows: T(n,k) = binomial(n+4,4) * binomial(n,k), 0 <= k <= n.

Original entry on oeis.org

1, 5, 5, 15, 30, 15, 35, 105, 105, 35, 70, 280, 420, 280, 70, 126, 630, 1260, 1260, 630, 126, 210, 1260, 3150, 4200, 3150, 1260, 210, 330, 2310, 6930, 11550, 11550, 6930, 2310, 330, 495, 3960, 13860, 27720, 34650, 27720, 13860, 3960, 495, 715, 6435, 25740, 60060, 90090, 90090, 60060, 25740, 6435, 715
Offset: 0

Views

Author

Harlan J. Brothers, Jun 19 2010

Keywords

Comments

The product of the pentatope numbers (A000332, beginning with fifth term) and Pascal's triangle (A007318). Also level 5 of Pascal's prism (A178819) read by rows: (i+4; 4, i-j, j), i >= 0, 0 <= j <= i.

Examples

			Triangle begins:
   1;
   5,   5;
  15,  30,  15;
  35, 105, 105,  35;
  70, 280, 420, 280,  70;
		

Crossrefs

Rows sum to A003472, shallow diagonals sum to A001873.

Programs

  • GAP
    T:=Flat(List([0..10], n-> List([0..n], k-> Binomial(n+4, 4)* Binomial(n, k) ))); # G. C. Greubel, Jan 22 2019
  • Magma
    /* As triangle */ [[Binomial(n+4,4)*Binomial(n,k): k in [0..n]]: n in [0.. 10]]; // Vincenzo Librandi, Oct 23 2017
    
  • Maple
    T:=(n,k)->binomial(n+4,4)*binomial(n,k): seq(seq(T(n,k),k=0..n),n=0..9); # Muniru A Asiru, Jan 22 2019
  • Mathematica
    Table[Multinomial[4, i-j, j], {i, 0, 9}, {j, 0, i}]//Column
  • PARI
    {T(n,k) = binomial(n+4, 4)*binomial(n, k)}; \\ G. C. Greubel, Jan 22 2019
    
  • Sage
    [[binomial(n+4, 4)*binomial(n, k) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Jan 22 2019
    

Formula

T(n,k) = C(n+4,4) * C(n,k), 0 <= k <= n.
For element a in A178819: a_(5, i, j) = (i+3; 4, i-j, j-1), i >= 1, 1 <= j <= i.
G.f.: 1/(1 - x - x*y)^5. - Ilya Gutkovskiy, Mar 20 2020

A211386 Expansion of 1/((1-2*x)^5*(1-x)).

Original entry on oeis.org

1, 11, 71, 351, 1471, 5503, 18943, 61183, 187903, 553983, 1579007, 4374527, 11829247, 31326207, 81461247, 208470015, 525991935, 1310457855, 3228041215, 7870611455, 19012780031, 45541752831, 108246597631, 255466668031, 598980165631, 1395931480063, 3235049897983
Offset: 0

Views

Author

R. J. Mathar, Feb 07 2013

Keywords

Comments

Occurs in the enumerations of inflations of code words babxxxdc [Albert et al. Sec 5.5.1]

Crossrefs

Cf. A003472 (first differences).

Programs

  • Mathematica
    CoefficientList[Series[1/((1-2x)^5(1-x)),{x,0,30}],x] (* or *) LinearRecurrence[ {11,-50,120,-160,112,-32},{1,11,71,351,1471,5503},30] (* Harvey P. Dale, Mar 02 2015 *)
  • PARI
    Vec(1/((1-2*x)^5*(1-x))+ O(x^30)) \\ Michel Marcus, Feb 12 2015

Formula

a(n) = 2^n*(24+18*n+23*n^2+6*n^3+n^4)/12-1.
a(0)=1, a(1)=11, a(2)=71, a(3)=351, a(4)=1471, a(5)=5503, a(n)=11*a(n-1)- 50*a(n-2)+ 120*a(n-3)-160*a(n-4)+112*a(n-5)-32*a(n-6). - Harvey P. Dale, Mar 02 2015

A213346 4-quantum transitions in systems of N>=4 spin 1/2 particles, in columns by combination indices.

Original entry on oeis.org

1, 10, 60, 6, 280, 84, 1120, 672, 28, 4032, 4032, 504, 13440, 20160, 5040, 120, 42240, 88704, 36960, 2640, 126720, 354816, 221760, 31680, 495, 366080, 1317888, 1153152, 274560, 12870, 1025024, 4612608, 5381376, 1921920, 180180, 2002
Offset: 4

Views

Author

Stanislav Sykora, Jun 12 2012

Keywords

Comments

For a general discussion, please see A213343.
This a(n) is for quadruple-quantum transitions (q = 4).
It lists the flattened triangle T(4;N,k) with rows N = 4,5,... and columns k = 0..floor((N-4)/2).

Examples

			Starting rows of the triangle:
  N | k = 0, 1, ..., floor((N-4)/2)
  4 |    1
  5 |   10
  6 |   60   6
  7 |  280  84
  8 | 1120 672 28
		

References

Crossrefs

Cf. A051288 (q=0), A213343 to A213345 (q=1 to 3), A213347 to A213352 (q=5 to 10).
Cf. A003472 (first column), A004310 (row sums).

Programs

  • Mathematica
    With[{q = 4}, Table[2^(n - q - 2 k)*Binomial[n, k] Binomial[n - k, q + k], {n, 14}, {k, 0, Floor[(n - q)/2]}]] // Flatten (* Michael De Vlieger, Nov 18 2019 *)
  • PARI
    See A213343; set thisq = 4

Formula

Set q = 4 in: T(q;N,k) = 2^(N-q-2*k)*binomial(N,k)*binomial(N-k,q+k)

A001816 Coefficients of x^n in Hermite polynomial H_{n+4}.

Original entry on oeis.org

12, 120, 720, 3360, 13440, 48384, 161280, 506880, 1520640, 4392960, 12300288, 33546240, 89456640, 233963520, 601620480, 1524105216, 3810263040, 9413591040, 23011000320, 55710842880, 133706022912, 318347673600, 752458137600, 1766640844800, 4122161971200
Offset: 0

Views

Author

Keywords

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 801.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Mathematica
    Table[Coefficient[HermiteH[n + 4, x], x, n], {n, 0, 25}] (* T. D. Noe, Aug 10 2012 *)
    LinearRecurrence[{10,-40,80,-80,32},{12,120,720,3360,13440},30] (* Harvey P. Dale, Jul 27 2025 *)
  • PARI
    a(n) = polcoeff(polhermite(n+4), n); \\ Michel Marcus, May 06 2022

Formula

a(n) = 12*A003472(n+4) = A060821(4+n, n).
G.f.: 12 ( 1 - 2 x )^(-5).
From Amiram Eldar, May 06 2022: (Start)
Sum_{n>=0} 1/a(n) = 5/9 - 2*log(2)/3.
Sum_{n>=0} (-1)^n/a(n) = 18*log(3/2) - 65/9. (End)

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jan 29 2001
Previous Showing 11-20 of 26 results. Next