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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A283338 Expansion of exp( Sum_{n>=1} -sigma_8(n)*x^n/n ) in powers of x.

Original entry on oeis.org

1, -1, -128, -2059, -6069, 210067, 3664420, 23366098, -116899962, -4133365357, -41809923367, -125160180169, 2447495850838, 42931762306584, 321967686614676, 281683012498569, -23874414003295851, -318729240693402530, -1992572289343189863
Offset: 0

Views

Author

Seiichi Manyama, Mar 05 2017

Keywords

Crossrefs

Column k=7 of A283272.
Cf. A023876 (exp( Sum_{n>=1} sigma_8(n)*x^n/n )).
Cf. exp( Sum_{n>=1} -sigma_k(n)*x^n/n ): A010815 (k=1), A073592 (k=2), A283263 (k=3), A283264 (k=4), A283271 (k=5), A283336 (k=6), A283337 (k=7), this sequence (k=8), A283339 (k=9), A283340 (k=10).

Formula

G.f.: Product_{n>=1} (1 - x^n)^(n^7).
a(n) = -(1/n)*Sum_{k=1..n} sigma_8(k)*a(n-k).

A283339 Expansion of exp( Sum_{n>=1} -sigma_9(n)*x^n/n ) in powers of x.

Original entry on oeis.org

1, -1, -256, -6305, -26335, 1321887, 32565169, 276211695, -2659962750, -111341327890, -1454216029918, -3323783801026, 227018039015019, 4636828146319845, 39615489757794355, -132865771935151820, -9075288352543844755, -132703303201618610765
Offset: 0

Views

Author

Seiichi Manyama, Mar 05 2017

Keywords

Crossrefs

Column k=8 of A283272.
Cf. A023877 (exp( Sum_{n>=1} sigma_9(n)*x^n/n )).
Cf. exp( Sum_{n>=1} -sigma_k(n)*x^n/n ): A010815 (k=1), A073592 (k=2), A283263 (k=3), A283264 (k=4), A283271 (k=5), A283336 (k=6), A283337 (k=7), A283338 (k=8), this sequence (k=9), A283340 (k=10).

Formula

G.f.: Product_{n>=1} (1 - x^n)^(n^8).
a(n) = -(1/n)*Sum_{k=1..n} sigma_9(k)*a(n-k).

A283340 Expansion of exp( Sum_{n>=1} -sigma_10(n)*x^n/n ) in powers of x.

Original entry on oeis.org

1, -1, -512, -19171, -111645, 8255899, 287477144, 3248973702, -56353404842, -2946880278857, -50078654012311, -24091665240825, 19437354184565824, 486126425619195338, 4607922953609319032, -63107867988829247005, -3101395214088243725145
Offset: 0

Views

Author

Seiichi Manyama, Mar 05 2017

Keywords

Crossrefs

Column k=9 of A283272.
Cf. A023878 (exp( Sum_{n>=1} sigma_10(n)*x^n/n )).
Cf. exp( Sum_{n>=1} -sigma_k(n)*x^n/n ): A010815 (k=1), A073592 (k=2), A283263 (k=3), A283264 (k=4), A283271 (k=5), A283336 (k=6), A283337 (k=7), A283338 (k=8), A283339 (k=9), this sequence (k=10).

Formula

G.f.: Product_{n>=1} (1 - x^n)^(n^9).
a(n) = -(1/n)*Sum_{k=1..n} sigma_10(k)*a(n-k).

A299211 Expansion of 1/(1 - x*Product_{k>=1} (1 - x^k)^k).

Original entry on oeis.org

1, 1, 0, -3, -6, -4, 12, 39, 52, -9, -186, -392, -285, 610, 2291, 3200, -150, -10626, -23487, -18841, 32957, 134848, 198246, 13961, -605248, -1409604, -1234474, 1744213, 7898753, 12209679, 2161666, -34344627, -84393284, -79993042, 90692470, 461463974, 749309529, 207447895, -1939084232
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 05 2018

Keywords

Crossrefs

Programs

  • Maple
    N:= 100: # for a(0)..a(N)
    S:= series(1/(1-x*mul((1-x^k)^k,k=1..N)),x,N+1):
    seq(coeff(S,x,i),i=0..N); # Robert Israel, Feb 05 2023
  • Mathematica
    nmax = 38; CoefficientList[Series[1/(1 - x Product[(1 - x^k)^k, {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - x*Product_{k>=1} (1 - x^k)^k).
a(0) = 1; a(n) = Sum_{k=1..n} A073592(k-1)*a(n-k).

A318784 Expansion of Product_{k>=1} 1/(1 - x^k)^(sigma_1(k)-k), where sigma_1(k) = sum of divisors of k (A000203).

Original entry on oeis.org

1, 0, 1, 1, 4, 2, 11, 6, 25, 20, 56, 44, 139, 107, 283, 266, 619, 567, 1317, 1242, 2680, 2705, 5403, 5539, 10947, 11339, 21291, 23013, 41494, 45213, 79991, 88312, 151546, 170908, 284901, 324421, 532505, 611227, 981002, 1142000, 1797451, 2105773, 3268765, 3855050, 5889704, 7004451
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 03 2018

Keywords

Comments

Convolution of A061256 and A073592.
Euler transform of A001065.

Crossrefs

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
          (sigma(d)-d), d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..50);  # Alois P. Heinz, Sep 03 2018
  • Mathematica
    nmax = 45; CoefficientList[Series[Product[1/(1 - x^k)^(DivisorSigma[1, k] - k), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 45; CoefficientList[Series[Exp[Sum[DivisorSigma[2, k] x^(2 k)/(k (1 - x^k)), {k, 1, nmax}]], {x, 0, nmax}], x]
    a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d (DivisorSigma[1, d] - d), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 45}]

Formula

G.f.: Product_{k>=1} 1/(1 - x^k)^A001065(k).
G.f.: exp(Sum_{k>=1} sigma_2(k)*x^(2*k)/(k*(1 - x^k))), where sigma_2(k) = sum of squares of divisors of k (A001157).
a(n) ~ exp(3^(2/3) * c^(1/3) * n^(2/3)/2 - Pi^2 * n^(1/3) / (4 * 3^(2/3) * c^(1/3)) - Pi^4/(288*c) - 1/8) * A^(3/2) * c^(1/8) / (3^(5/8) * (2*Pi)^(11/24) * n^(5/8)), where c = (Pi^2 - 6)*Zeta(3) and A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Sep 03 2018

A294404 E.g.f.: exp(-Sum_{n>=1} sigma_2(n) * x^n).

Original entry on oeis.org

1, -1, -9, -31, -23, 3399, 41311, 473129, 1284081, -79051537, -2447228249, -52444297071, -712806368999, -2221410364681, 331443685309647, 15068893004257049, 460836352976093281, 10298306504802529119, 122928784866003823831, -3359583359629857247807
Offset: 0

Views

Author

Seiichi Manyama, Oct 30 2017

Keywords

Crossrefs

E.g.f.: exp(-Sum_{n>=1} sigma_k(n) * x^n): A294402 (k=0), A294403 (k=1), this sequence (k=2).

Programs

  • PARI
    N=66; x='x+O('x^N); Vec(serlaplace(exp(-sum(k=1, N, sigma(k, 2)*x^k))))

Formula

a(0) = 1 and a(n) = (-1) * (n-1)! * Sum_{k=1..n} k*A001157(k)*a(n-k)/(n-k)! for n > 0.
E.g.f.: Product_{k>=1} (1 - x^k)^f(k), where f(k) = (1/k) * Sum_{j=1..k} gcd(k,j)^3. - Ilya Gutkovskiy, Aug 17 2021

A294808 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of Product_{j>=1} (1-j^(k*j)*x^j)^j in powers of x.

Original entry on oeis.org

1, 1, -1, 1, -1, -2, 1, -1, -8, -1, 1, -1, -32, -73, 0, 1, -1, -128, -2155, -927, 4, 1, -1, -512, -58921, -259701, -13969, 4, 1, -1, -2048, -1593811, -67045719, -48496253, -254580, 7, 1, -1, -8192, -43044673, -17178209325, -152513227585, -13001952944, -5288596, 3
Offset: 0

Views

Author

Seiichi Manyama, Nov 09 2017

Keywords

Examples

			Square array begins:
    1,      1,         1,             1,                1, ...
   -1,     -1,        -1,            -1,               -1, ...
   -2,     -8,       -32,          -128,             -512, ...
   -1,    -73,     -2155,        -58921,         -1593811, ...
    0,   -927,   -259701,     -67045719,     -17178209325, ...
    4, -13969, -48496253, -152513227585, -476819162106101, ...
		

Crossrefs

Columns k=0..2 give A073592, A294809, A294953.
Rows n=0..2 give A000012, (-1)*A000012, (-1)*A004171.

Formula

A(0,k) = 1 and A(n,k) = -(1/n) * Sum_{j=1..n} (Sum_{d|j} d^(2+k*j)) * A(n-j,k) for n > 0.

A301624 G.f. A(x) satisfies: A(x) = Product_{k>=1} (1 - x^k*A(x)^k)^k.

Original entry on oeis.org

1, -1, -1, 4, 1, -17, -6, 118, -8, -876, 625, 5966, -7486, -41937, 75969, 306312, -768637, -2164992, 7487063, 14461466, -70259884, -89410774, 646971980, 459817892, -5861484630, -1128608133, 52082250637, -15894742662, -453574650852, 366848121166, 3866670213663, -5215687717614
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 24 2018

Keywords

Examples

			G.f. A(x) = 1 - x - x^2 + 4*x^3 + x^4 - 17*x^5 - 6*x^6 + 118*x^7 - 8*x^8 - 876*x^9 + 625*x^10 + ...
G.f. A(x) satisfies: A(x) = (1 - x*A(x)) * (1 - x^2*A(x)^2)^2 * (1 - x^3*A(x)^3)^3 * (1 - x^4*A(x)^4)^4 * ...
log(A(x)) = -x - 3*x^2/2 + 8*x^3/3 + 13*x^4/4 - 51*x^5/5 - 120*x^6/6 + 538*x^7/7 + 781*x^8/8 - 5419*x^9/9 - 3053*x^10/10 + ... + A281267(n)*x^n/n + ...
		

Crossrefs

Programs

  • Maple
    with(numtheory):
    Order := 33:
    Gser := solve(series(x*exp(add(sigma[2](n)*x^n/n, n = 1..32)), x) = y, x):
    seq(coeff(Gser, y^k), k = 1..32); # Peter Bala, Feb 09 2020

Formula

From Peter Bala, Feb 09 2020: (Start)
A(x) = 1/x * series reversion of ( exp( Sum_{n >= 1} sigma_2(n)*x^n/n ) ), where sigma_2(n) = A001157(n).
Equivalently, the o.g.f. A(x) satisfies [x^n](1/A(x))^n = sigma_2(n) for n >= 1. Cf. A066398. (End)
A(x) equals (1/x) * series reversion of (x * the o.g.f. for the sequence of planar partitions A000219). - Peter Bala, Feb 11 2020

A303173 a(n) = [x^n] Product_{k=1..n} (1 - x^k)^(n-k+1).

Original entry on oeis.org

1, -1, 0, 4, -7, 0, 13, 10, -92, 21, 720, -2019, 1193, 6281, -18054, 16111, 11059, -14653, -57685, -86620, 1281406, -3454742, 2383734, 9409968, -30397071, 43327680, -56130326, 128981571, -73487834, -1219918457, 5059678044, -7826243881, -4131571113, 38850603452
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 19 2018

Keywords

Examples

			a(0) = 1;
a(1) = [x^1] (1 - x) = -1;
a(2) = [x^2] (1 - x)^2*(1 - x^2) = 0;
a(3) = [x^3] (1 - x)^3*(1 - x^2)^2*(1 - x^3) = 4;
a(4) = [x^4] (1 - x)^4*(1 - x^2)^3*(1 - x^3)^2*(1 - x^4) = -7;
a(5) = [x^5] (1 - x)^5*(1 - x^2)^4*(1 - x^3)^3*(1 - x^4)^2*(1 - x^5) = 0, etc.
...
The table of coefficients of x^k in expansion of Product_{k=1..n} (1 - x^k)^(n-k+1) begins:
n = 0: (1),  0,  0,  0,    0,   0,  ...
n = 1:  1, (-1), 0,  0,    0,   0,  ...
n = 2:  1,  -2, (0), 2,   -1,   0,  ...
n = 3:  1,  -3,  1, (4),  -2,  -2,  ...
n = 4:  1,  -4,  3,  6,  (-7), -2,  ...
n = 5:  1,  -5,  6,  7,  -16,  (0), ...
		

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[(1 - x^k)^(n - k + 1), {k, 1, n}], {x, 0, n}], {n, 0, 33}]

A276552 Expansion of Product_{k>0} (1 - x^k)^(k*3).

Original entry on oeis.org

1, -3, -3, 8, 12, 9, -29, -54, -51, 8, 168, 273, 270, -18, -546, -1220, -1539, -969, 796, 3693, 6591, 8098, 5412, -2568, -16053, -31524, -42195, -38684, -11868, 41994, 117630, 193365, 235497, 197758, 42852, -247224, -639547, -1041432, -1291425, -1184100, -520650
Offset: 0

Views

Author

Seiichi Manyama, Apr 10 2017

Keywords

Crossrefs

Column k=3 of A276554.
Product_{k>0} (1-x^k)^(k*m): A255610 (m=-3), A073592 (m=1), A276551 (m=2), this sequence (m=3).
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