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 1-10 of 10 results.

A036224 Expansion of (-1+1/(1-6*x)^6)/(36*x); related to A036084.

Original entry on oeis.org

1, 21, 336, 4536, 54432, 598752, 6158592, 60046272, 560431872, 5043886848, 44019376128, 374164697088, 3108445175808, 25311625003008, 202493000024064, 1594632375189504, 12381851383824384, 94927527275986944
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Sage
    [lucas_number2(n, 6, 0)*binomial(n,5)/6^7for n in range(6, 24)] # Zerinvary Lajos, Mar 13 2009

Formula

a(n) = 6^(n-1)*binomial(n+6, 5);
g.f. (-1+(1-6*x)^(-6))/(x*6^2).

A075513 Triangle read by rows. T(n, m) are the coefficients of Sidi polynomials.

Original entry on oeis.org

1, -1, 2, 1, -8, 9, -1, 24, -81, 64, 1, -64, 486, -1024, 625, -1, 160, -2430, 10240, -15625, 7776, 1, -384, 10935, -81920, 234375, -279936, 117649, -1, 896, -45927, 573440, -2734375, 5878656, -5764801, 2097152, 1, -2048, 183708, -3670016, 27343750, -94058496, 161414428, -134217728, 43046721
Offset: 1

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Author

Wolfdieter Lang, Oct 02 2002

Keywords

Comments

Coefficients of the Sidi polynomials (-1)^(n-1)*D_{n-1,1,n-1}(x), for n >=1, where D_{k,n,m}(z) is given in Theorem 4.2., p. 862, of Sidi [1980].
The row polynomials p(n, x) := Sum_{m=0..n-1} a(n, m)x^m, n >= 1, are obtained from ((Eu(x)^n)*(x-1)^n)/(n*x), where Eu(x) := xd/dx is the Euler-derivative with respect to x.
The row polynomials p(n, y) := Sum_{m=0..n-1} a(n, m)*y^m, n >= 1, are also obtained from ((d^m/dx^m)((exp(x)-1)^m)/m)/exp(x) after replacement of exp(x) by y. Here (d^m/dx^m)f(x), m >= 1, denotes m-fold differentiation of f(x) with respect to x.
b(k,m,n) := (Sum_{p=0..m-1} (a(m, p)*((p+1)*k)^n))/(m-1)!, n >= 0, has g.f. 1/Product_{p=1..m} (1 - k*p*x) for k = 1, 2,... and m = 1, 2,...
The (signed) row sums give A000142(n-1), n >= 1, (factorials) and (unsigned) A074932(n).
The (unsigned) columns give A000012 (powers of 1), 2*A001787(n+1), (3^2)*A027472(n), (4^3)*A038846(n-1), (5^4)*A036071(n-5), (6^5)*A036084(n-6), (7^6)*A036226(n-7), (8^7)*A053107(n-8) for m=0..7.
Right edge of triangle is A000169. - Michel Marcus, May 17 2013

Examples

			The triangle T(n, m)  begins:
  n\m 0     1      2        3        4         5         6          7       8
  1:  1
  2: -1     2
  3:  1    -8      9
  4: -1    24    -81       64
  5:  1   -64    486    -1024      625
  6: -1   160  -2430    10240   -15625      7776
  7:  1  -384  10935   -81920   234375   -279936    117649
  8: -1   896 -45927   573440 -2734375   5878656  -5764801    2097152
  9:  1 -2048 183708 -3670016 27343750 -94058496 161414428 -134217728 4304672
  [Reformatted by _Wolfdieter Lang_, Oct 12 2022]
-----------------------------------------------------------------------------
p(2,x) = -1+2*x = (1/(2*x))*x*(d/dx)*x*(d/dx)*(x-1)^2.
		

References

  • A. Sidi, Practical Extrapolation Methods: Theory and Applications, Cambridge University Press, Cambridge, 2003.

Crossrefs

Programs

  • Maple
    # Assuming offset 0.
    seq(seq((-1)^(n-k)*binomial(n, k)*(k+1)^n, k=0..n), n=0..8);
    # Alternative:
    egf := x -> 1/(exp(LambertW(-exp(-x)*x*y) + x) - x*y):
    ser := x -> series(egf(x), x, 12):
    row := n -> seq(coeff(n!*coeff(ser(x), x, n), y, k), k=0..n):
    seq(print(row(n)), n = 0..8); # Peter Luschny, Oct 21 2022
  • Mathematica
    p[n_, x_] := p[n, x] = Nest[ x*D[#, x]& , (x-1)^n, n]/(n*x); a[n_, m_] := Coefficient[ p[n, x], x, m]; Table[a[n, m], {n, 1, 9}, {m, 0, n-1}] // Flatten (* Jean-François Alcover, Jul 03 2013 *)
  • PARI
    tabl(nn) = {for (n=1, nn, for (m=0, n-1, print1((-1)^(n-m-1)*binomial(n-1, m)*(m+1)^(n-1), ", ");); print(););} \\ Michel Marcus, May 17 2013

Formula

T(n, m) = ((-1)^(n-m-1)) binomial(n-1, m)*(m+1)^(n-1), n >= m+1 >= 1, else 0.
G.f. for m-th column: ((m+1)^m)(x/(1+(m+1)*x))^(m+1), m >= 0.
E.g.f.: -LambertW(-x*y*exp(-x))/((1+LambertW(-x*y*exp(-x)))*x*y). - Vladeta Jovovic, Feb 13 2008 [corrected for offset 0 <= m <= n. For offset n >= 1 take the integral over x. - Wolfdieter Lang, Oct 12 2022]
T(n, k) = S(n, k+1) / n where S(, ) is triangle in A258773. - Michael Somos, May 13 2018
E.g.f. of column k, with offset n >= 0: exp(-(k + 1)*x)*((k + 1)*x)^k/k!. - Wolfdieter Lang, Oct 20 2022
E.g.f: 1/(exp(LambertW(-exp(-x)*x*y) + x) - x*y) assuming offset = 0. - Peter Luschny, Oct 21 2022

A050982 5-idempotent numbers.

Original entry on oeis.org

1, 30, 525, 7000, 78750, 787500, 7218750, 61875000, 502734375, 3910156250, 29326171875, 213281250000, 1510742187500, 10458984375000, 70971679687500, 473144531250000, 3105010986328125, 20091247558593750, 128360748291015625, 810699462890625000
Offset: 5

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Author

Keywords

Comments

Number of n-permutations of 6 objects: t,u,v,z,x, y with repetition allowed, containing exactly five u's. Example: a(6)=30 because we have uuuuut, uuuutu, uuutuu, uutuuu, utuuuu, tuuuuu, uuuuuv, uuuuvu, uuuvuu, uuvuuu, uvuuuu, vuuuuu, uuuuuz, uuuuzu, uuuzuu, uuzuuu, uzuuuu, zuuuuu, uuuuux, uuuuxu, uuuxuu, uuxuuu, uxuuuu, xuuuuu, uuuuuy, uuuuyu, uuuyuu, uuyuuu, uyuuuu, yuuuuu. - Zerinvary Lajos, Jun 16 2008

References

  • Louis Comtet, Advanced Combinatorics, Reidel, 1974, p. 91, #43.

Crossrefs

Programs

Formula

a(n) = C(n, 5)*5^(n-5).
G.f.: x^5/(1-5*x)^6. - Zerinvary Lajos, Aug 06 2008
From Amiram Eldar, Apr 17 2022: (Start)
Sum_{n>=5} 1/a(n) = 6400*log(5/4) - 17125/12.
Sum_{n>=5} (-1)^(n+1)/a(n) = 32400*log(6/5) - 23625/4. (End)

A036226 Expansion of 1/(1-7*x)^7.

Original entry on oeis.org

1, 49, 1372, 28812, 504210, 7764834, 108707676, 1413199788, 17311697403, 201969803035, 2262061793992, 24471395771368, 256949655599364, 2628792630362724, 26287926303627240, 257621677775546952
Offset: 0

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Author

Keywords

Comments

With a different offset, number of n-permutations (n >= 6) of 8 objects: r, s, t, u, v, z, x, y with repetition allowed, containing exactly six (6) u's. - Zerinvary Lajos, Jun 16 2008

Crossrefs

Cf. A036084.

Programs

  • Magma
    [7^n* Binomial(n+6, 6): n in [0..20]]; // Vincenzo Librandi, Oct 12 2011
  • Maple
    seq(binomial(n+6,6)*7^n,n=0..16); # Zerinvary Lajos, Jun 16 2008
  • Mathematica
    CoefficientList[Series[1/(1-7x)^7,{x,0,20}],x] (* or *) LinearRecurrence[ {49,-1029,12005,-84035,352947,-823543,823543},{1,49,1372,28812,504210,7764834,108707676},20] (* Harvey P. Dale, Feb 21 2013 *)
  • Sage
    [lucas_number2(n, 7, 0)*binomial(n,6)/7^6 for n in range(6, 22)] # Zerinvary Lajos, Mar 13 2009
    

Formula

a(n) = 7^n*binomial(n+6, 6).
G.f.: 1/(1-7*x)^7.
a(n) = 49*a(n-1) - 1029*a(n-2) + 12005*a(n-3) - 84035*a(n-4) + 352947*a(n-5) - 823543*a(n-6) + 823543*a(n-7), a(0)=1, a(1)=49, a(2)=1372, a(3)=28812, a(4)=504210, a(5)=7764834, a(6)=108707676. - Harvey P. Dale, Feb 21 2013

A140404 a(n) = binomial(n+5, 5)*7^n.

Original entry on oeis.org

1, 42, 1029, 19208, 302526, 4235364, 54353838, 652246056, 7419298887, 80787921214, 848273172747, 8636963213424, 85649885199788, 830145041167176, 7886377891088172, 73606193650156272, 676256904160810749, 6126091955339109138, 54794489156088698401, 484498640959100070072
Offset: 0

Views

Author

Zerinvary Lajos, Jun 16 2008

Keywords

Comments

With a different offset, number of n-permutations of 8 objects:r,s,t,u,v,z,x,y with repetition allowed, containing exactly five (5) u's. Example: a(1)=42 because we have
uuuuur, uuuuru, uuuruu, uuruuu, uruuuu, ruuuuu
uuuuus, uuuusu, uuusuu, uusuuu, usuuuu, suuuuu,
uuuuut, uuuutu, uuutuu, uutuuu, utuuuu, tuuuuu,
uuuuuv, uuuuvu, uuuvuu, uuvuuu, uvuuuu, vuuuuu,
uuuuuz, uuuuzu, uuuzuu, uuzuuu, uzuuuu, zuuuuu,
uuuuux, uuuuxu, uuuxuu, uuxuuu, uxuuuu, xuuuuu,
uuuuuy, uuuuyu, uuuyuu, uuyuuu, uyuuuu, yuuuuu.

Crossrefs

Programs

  • Magma
    [7^n* Binomial(n+5, 5): n in [0..20]]; // Vincenzo Librandi, Oct 12 2011
    
  • Maple
    seq(binomial(n+5,5)*7^n,n=0..17);
  • Mathematica
    Table[Binomial[n+5,5]7^n,{n,0,20}] (* or *) LinearRecurrence[ {42,-735,6860,-36015,100842,-117649},{1,42,1029,19208,302526,4235364},21] (* Harvey P. Dale, Sep 08 2011 *)
  • PARI
    a(n)=binomial(n+5,5)*7^n \\ Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: 1/(1-7*x)^6. - Zerinvary Lajos, Aug 06 2008
a(n) = 42*a(n-1) - 735*a(n-2) + 6860*a(n-3) - 36015*a(n-4) + 100842*a(n-5) - 117649*a(n-6). - Harvey P. Dale, Sep 08 2011
From Amiram Eldar, Aug 28 2022: (Start)
Sum_{n>=0} 1/a(n) = 45360*log(7/6) - 27965/4.
Sum_{n>=0} (-1)^n/a(n) = 143360*log(8/7) - 229705/12. (End)

A053109 Expansion of 1/(1-10*x)^10.

Original entry on oeis.org

1, 100, 5500, 220000, 7150000, 200200000, 5005000000, 114400000000, 2431000000000, 48620000000000, 923780000000000, 16796000000000000, 293930000000000000, 4974200000000000000, 81719000000000000000
Offset: 0

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Author

Keywords

Comments

This is the tenth member of the k-family of sequences a(k,n) := k^n*binomial(n+k-1,k-1) starting with A000012 (powers of 1), A001787(n+1), A027472(n+3), A038846, A036071, A036084, A036226, A053107-9 for k=1..10.

Programs

  • GAP
    List([0..15],n->10^n*Binomial(n+9,9)); # Muniru A Asiru, Aug 16 2018
  • Magma
    [10^n*Binomial(n+9, 9): n in [0..30]]; // G. C. Greubel, Aug 16 2018
    
  • Maple
    seq(coeff(series(1/(1-10*x)^10, x, n+1), x, n), n = 0 .. 15); # Muniru A Asiru, Aug 16 2018
  • Mathematica
    CoefficientList[Series[1/(1-10x)^10,{x,0,20}],x] (* or *) Table[10^n Binomial[n+9,9],{n,0,20}] (* Harvey P. Dale, May 19 2011 *)
  • PARI
    vector(30,n,n--; 10^n*binomial(n+9, 9)) \\ G. C. Greubel, Aug 16 2018
    
  • Sage
    [lucas_number2(n, 10, 0)*binomial(n,9)/10 ^9 for n in range(9, 24)] # Zerinvary Lajos, Mar 13 2009
    

Formula

a(n) = 10^n*binomial(n+9, 9);
G.f.: 1/(1-10*x)^10.

A172501 a(n) = binomial(n+8,8)*6^n.

Original entry on oeis.org

1, 54, 1620, 35640, 641520, 10007712, 140107968, 1801388160, 21616657920, 244988789760, 2645878929408, 27420927086592, 274209270865920, 2657720625315840, 25058508752977920, 230538280527396864, 2074844524746571776, 18307451688940339200, 158664581304149606400
Offset: 0

Views

Author

Zerinvary Lajos, Feb 05 2010

Keywords

Comments

With a different offset, number of n-permutations (n>=8) of 7 objects: r, s, t, u, v, z, x, y with repetition allowed, containing exactly eight (8) u's.

Crossrefs

Programs

  • Magma
    [6^n* Binomial(n+8, 8): n in [0..20]]; // Vincenzo Librandi, Oct 12 2011
    
  • Mathematica
    Table[Binomial[n + 8, 8]*6^n, {n, 0, 20}]
  • PARI
    Vec(1 / (1 - 6*x)^9 + O(x^30)) \\ Colin Barker, Jul 24 2017

Formula

From Colin Barker, Jul 24 2017: (Start)
G.f.: 1 / (1 - 6*x)^9.
a(n) = (2^(-7 + n)*3^(-2 + n)*(1 + n)*(2 + n)*(3 + n)*(4 + n)*(5 + n)*(6 + n)*(7 + n)*(8 + n)) / 35.
(End)
From Amiram Eldar, Aug 29 2022: (Start)
Sum_{n>=0} 1/a(n) = 4785948/7 - 3750000*log(6/5).
Sum_{n>=0} (-1)^n/a(n) = 39530064*log(7/6) - 213275484/35. (End)

A173123 a(n) = binomial(n+9,9)*6^n.

Original entry on oeis.org

1, 60, 1980, 47520, 926640, 15567552, 233513280, 3202467840, 40831464960, 489977579520, 5585744406528, 60935393525760, 639821632020480, 6496650417438720, 64038411257610240, 614768748073058304, 5763457013184921600, 52888193768049868800, 475993743912448819200
Offset: 0

Views

Author

Zerinvary Lajos, Feb 10 2010

Keywords

Comments

With a different offset, number of n-permutations (n>=9) of 7 objects: r, s, t, u, v, z, x, y with repetition allowed, containing exactly 9 u's.

Crossrefs

Programs

  • Magma
    [6^n* Binomial(n+9, 9): n in [0..20]]; // Vincenzo Librandi, Oct 12 2011
  • Mathematica
    Table[Binomial[n + 9, 9]*6^n, {n, 0, 20}]

Formula

a(n) = C(n + 9, 9)*6^n.
From Chai Wah Wu, Nov 12 2021: (Start)
a(n) = 60*a(n-1) - 1620*a(n-2) + 25920*a(n-3) - 272160*a(n-4) + 1959552*a(n-5) - 9797760*a(n-6) + 33592320*a(n-7) - 75582720*a(n-8) + 100776960*a(n-9) - 60466176*a(n-10) for n > 9.
G.f.: 1/(6*x - 1)^10. (End)
From Amiram Eldar, Aug 29 2022: (Start)
Sum_{n>=0} 1/a(n) = 21093750*log(6/5) - 107683641/28.
Sum_{n>=0} (-1)^n/a(n) = 311299254*log(7/6) - 959739813/20. (End)

A173124 a(n) = binomial(n+10,10)*6^n.

Original entry on oeis.org

1, 66, 2376, 61776, 1297296, 23351328, 373621248, 5444195328, 73496636928, 930957401088, 11171488813056, 127964326404096, 1407607590445056, 14942295960109056, 153692187018264576, 1536921870182645760, 14984988234280796160, 142798123173734645760, 1332782482954856693760
Offset: 0

Views

Author

Zerinvary Lajos, Feb 10 2010

Keywords

Comments

With a different offset, number of n-permutations (n>=10) of 7 objects: r, s, t, u, v, z, x, with repetition allowed, containing exactly 10 u's.

Crossrefs

Programs

  • Magma
    [6^n* Binomial(n+10, 10): n in [0..20]]; // Vincenzo Librandi, Oct 12 2011
  • Mathematica
    Table[Binomial[n + 10, 10]*6^n, {n, 0, 20}]

Formula

From Chai Wah Wu, Nov 12 2021: (Start)
a(n) = 66*a(n-1) - 1980*a(n-2) + 35640*a(n-3) - 427680*a(n-4) + 3592512*a(n-5) - 21555072*a(n-6) + 92378880*a(n-7) - 277136640*a(n-8) + 554273280*a(n-9) - 665127936*a(n-10) + 362797056*a(n-11) for n > 10.
G.f.: -1/(6*x - 1)^11. (End)
From Amiram Eldar, Sep 04 2022: (Start)
Sum_{n>=0} 1/a(n) = 897363955/42 - 117187500*log(6/5).
Sum_{n>=0} (-1)^n/a(n) = 2421216420*log(7/6) - 2239392937/6. (End)

A293270 a(n) = n^n*binomial(2*n-1, n).

Original entry on oeis.org

1, 1, 12, 270, 8960, 393750, 21555072, 1413199788, 107961384960, 9418192087590, 923780000000000, 100633991211229476, 12055263261877075968, 1575041416811693275900, 222887966509090352332800, 33962507149515380859375000, 5543988061027763016035205120
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 04 2017

Keywords

Comments

The n-th term of the n-fold convolution of the powers of n.

Crossrefs

Programs

  • Mathematica
    Join[{1}, Table[n^n Binomial[2 n - 1, n], {n, 1, 16}]]
    Join[{1}, Table[(-1)^n n^n Binomial[-n, n], {n, 1, 16}]]
    Table[SeriesCoefficient[1/(1 - n x)^n, {x, 0, n}], {n, 0, 16}]
  • PARI
    a(n) = n^n*binomial(2*n-1, n); \\ Altug Alkan, Oct 04 2017

Formula

a(n) = [x^n] 1/(1 - n*x)^n.
a(n) ~ 2^(2*n-1)*n^n/sqrt(Pi*n).
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