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 17 results. Next

A299105 Expansion of 1/(1 - x*Product_{k>=1} (1 - x^k)).

Original entry on oeis.org

1, 1, 0, -2, -3, -1, 5, 10, 7, -9, -29, -30, 10, 77, 108, 22, -184, -351, -207, 372, 1041, 969, -516, -2835, -3655, -284, 6990, 12190, 5977, -14957, -37044, -30994, 24144, 103374, 122409, -7715, -262704, -420585, -162274, 589068, 1309674, 972747, -1057935, -3742955
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 02 2018

Keywords

Crossrefs

Antidiagonal sums of A286354.
Cf. similar sequences: A067687, A299106, A299208, A302017, A318581, A318582, A331484.

Programs

  • Mathematica
    nmax = 43; CoefficientList[Series[1/(1 - x Product[1 - x^k, {k, 1, nmax}]), {x, 0, nmax}], x]
    nmax = 43; CoefficientList[Series[1/(1 - x QPochhammer[x, x]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - x*Product_{k>=1} (1 - x^k)).
a(0) = 1; a(n) = Sum_{k=1..n} A010815(k-1)*a(n-k).

A008705 Coefficient of x^n in (Product_{m=1..n}(1-x^m))^n.

Original entry on oeis.org

1, -1, -1, 5, -5, -6, 11, 41, -125, -85, 1054, -2069, -209, 8605, -15625, 3990, 14035, 36685, -130525, -254525, 1899830, -3603805, -134905, 13479425, -25499225, 23579969, -64447293, 237487433, -133867445, -1795846200, 6309965146, -6788705842, -11762712973
Offset: 0

Views

Author

T. Forbes (anthony.d.forbes(AT)googlemail.com)

Keywords

Comments

Degree of resulting polynomial is A002411(n). - Michel Marcus, Sep 05 2013
The Gauss congruences a(n*p^k) == a(n*p^(k-1)) (mod p^k) hold for all primes p and all positive integers n and k. - Peter Bala, Jan 31 2022
Conjectures: the supercongruences a(p) == -1 - p (mod p^2) and a(2*p) == p - 1 (mod p^2) hold for all primes p >= 3. - Peter Bala, Apr 18 2023

Examples

			(1-x)^1 = -x + 1, hence a(1) = -1.
(1-x^2)^2*(1-x)^2 = x^6 - 2*x^5 - x^4 + 4*x^3 - x^2 - 2*x + 1, hence a(2) = -1.
		

Crossrefs

Bisections: A262308, A262309.
Main diagonal of A286354.

Programs

  • Maple
    C5:=proc(r) local t1,n; t1:=mul((1-x^n)^r,n=1..r+2); series(t1,x,r+1); coeff(%,x,r); end;
    [seq(C5(i),i=0..30)]; # N. J. A. Sloane, Oct 04 2015
    # second Maple program:
    b:= proc(n, k) option remember; `if`(n=0, 1, -k*
          add(numtheory[sigma](j)*b(n-j, k), j=1..n)/n)
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..35);  # Alois P. Heinz, Jun 21 2018
  • Mathematica
    With[{m = 40}, Table[SeriesCoefficient[Series[(Product[1-x^j, {j, n}])^n, {x, 0, m}], n], {n, 0, m}]] (* G. C. Greubel, Sep 09 2019 *)
  • PARI
    a(n) = polcoeff(prod(m = 1, n, (1-x^m)^n), n); \\ Michel Marcus, Sep 05 2013

Formula

a(n) = [x^n] exp(-n*Sum_{k>=1} x^k/(k*(1 - x^k))). - Ilya Gutkovskiy, May 30 2018

Extensions

More terms from Michel Marcus, Sep 05 2013
a(0)=1 prepended by N. J. A. Sloane, Oct 04 2015

A360401 a(n) = A356133(A360393(n)).

Original entry on oeis.org

2, 4, 11, 17, 25, 38, 43, 56, 64, 71, 79, 92, 101, 106, 119, 124, 133, 146, 151, 164, 173, 178, 191, 197, 206, 218, 227, 233, 242, 253, 260, 272, 280, 287, 295, 308, 317, 322, 335, 341, 350, 362, 371, 377, 385, 398, 403, 415, 425, 430, 443, 449, 457, 470
Offset: 1

Views

Author

Clark Kimberling, Mar 11 2023

Keywords

Comments

This is the third of four sequences that partition the positive integers. Suppose that u = (u(n)) and v = (v(n)) are increasing sequences of positive integers. Let u' and v' be their (increasing) complements, and consider these four sequences:
(1) u o v, defined by (u o v)(n) = u(v(n));
(2) u o v';
(3) u' o v;
(4) v' o u'.
Every positive integer is in exactly one of the four sequences. Their limiting densities are 4/9, 2/9, 2/9, 1/9 (and likewise for A360394-A360397 and A360402-A360405).

Examples

			(1)  u o v = (5, 8, 10, 12, 15, 16, 18, 21, 24, 26, 27, 30, 31, 35, 37, 39, ...) = A360398
(2)  u o v' = (1, 3, 6, 9, 14, 19, 23, 28, 33, 36, 41, 46, 51, 54, 60, 63, 68, ...) = A360399
(3)  u' o v = (7, 13, 20, 22, 29, 32, 34, 40, 47, 49, 53, 58, 62, 67, 74, 76, ...) = A360400
(4)  u' o v' = (2, 4, 11, 17, 25, 38, 43, 56, 64, 71, 79, 92, 101, 106, 119, ...) = A360401
		

Crossrefs

Cf. A026530, A356133, A360392, A360393, A360398, A286354, A286355, A360394 (intersections instead of results of composition), A360402-A360405.

Programs

  • Mathematica
    z = 2000;
    u = Accumulate[1 + ThueMorse /@ Range[0, 600]]; (* A026430 *)
    u1 = Complement[Range[Max[u]], u];  (* A356133 *)
    v = u + 2;  (* A360392 *)
    v1 = Complement[Range[Max[v]], v];  (* A360393 *)
    zz = 100;
    Table[u[[v[[n]]]], {n, 1, zz}]    (* A360398 *)
    Table[u[[v1[[n]]]], {n, 1, zz}]   (* A360399 *)
    Table[u1[[v[[n]]]], {n, 1, zz}]   (* A360400 *)
    Table[u1[[v1[[n]]]], {n, 1, zz}]  (* A360401 *)

A010840 Expansion of Product_{k>=1} (1-x^k)^40.

Original entry on oeis.org

1, -40, 740, -8320, 62530, -322048, 1085240, -1799680, -2821065, 26012480, -66837420, 35093760, 268749870, -783902720, 526221400, 1691816960, -3960854625, 1042577120, 5103133240, -380798080, -10159511430
Offset: 0

Views

Author

Keywords

References

  • Newman, Morris; A table of the coefficients of the powers of eta(tau). Nederl. Akad. Wetensch. Proc. Ser. A. 59 = Indag. Math. 18 (1956), 204-216.

Crossrefs

Column k=40 of A286354.
Cf. A000203.

Formula

a(0) = 1, a(n) = -(40/n) * Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Aug 13 2023

A319933 A(n, k) = [x^k] DedekindEta(x)^n, square array read by descending antidiagonals, A(n, k) for n >= 0 and k >= 0.

Original entry on oeis.org

1, 0, 1, 0, -1, 1, 0, -1, -2, 1, 0, 0, -1, -3, 1, 0, 0, 2, 0, -4, 1, 0, 1, 1, 5, 2, -5, 1, 0, 0, 2, 0, 8, 5, -6, 1, 0, 1, -2, 0, -5, 10, 9, -7, 1, 0, 0, 0, -7, -4, -15, 10, 14, -8, 1, 0, 0, -2, 0, -10, -6, -30, 7, 20, -9, 1, 0, 0, -2, 0, 8, -5, 0, -49, 0, 27, -10, 1
Offset: 0

Views

Author

Peter Luschny, Oct 02 2018

Keywords

Comments

The columns are generated by polynomials whose coefficients constitute the triangle of signed D'Arcais numbers A078521 when multiplied with n!.

Examples

			[ 0] 1,   0,   0,    0,     0,    0,     0,     0,     0,     0, ... A000007
[ 1] 1,  -1,  -1,    0,     0,    1,     0,     1,     0,     0, ... A010815
[ 2] 1,  -2,  -1,    2,     1,    2,    -2,     0,    -2,    -2, ... A002107
[ 3] 1,  -3,   0,    5,     0,    0,    -7,     0,     0,     0, ... A010816
[ 4] 1,  -4,   2,    8,    -5,   -4,   -10,     8,     9,     0, ... A000727
[ 5] 1,  -5,   5,   10,   -15,   -6,    -5,    25,    15,   -20, ... A000728
[ 6] 1,  -6,   9,   10,   -30,    0,    11,    42,     0,   -70, ... A000729
[ 7] 1,  -7,  14,    7,   -49,   21,    35,    41,   -49,  -133, ... A000730
[ 8] 1,  -8,  20,    0,   -70,   64,    56,     0,  -125,  -160, ... A000731
[ 9] 1,  -9,  27,  -12,   -90,  135,    54,   -99,  -189,   -85, ... A010817
[10] 1, -10,  35,  -30,  -105,  238,     0,  -260,  -165,   140, ... A010818
    A001489,  v , A167541, v , A319931,  v ,         diagonal: A008705
           A080956       A319930      A319932
		

References

  • G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers. Fifth ed., Clarendon Press, Oxford, 2003.

Crossrefs

Transpose of A286354.
Cf. A078521, A319574 (JacobiTheta3).

Programs

  • Julia
    # DedekindEta is defined in A000594
    for n in 0:10
        DedekindEta(10, n) |> println
    end
  • Maple
    DedekindEta := (x, n) -> mul(1-x^j, j=1..n):
    A319933row := proc(n, len) series(DedekindEta(x, len)^n, x, len+1):
    seq(coeff(%, x, j), j=0..len-1) end:
    seq(print([n], A319933row(n, 10)), n=0..10);
  • Mathematica
    eta[x_, n_] := Product[1 - x^j, {j, 1, n}];
    A[n_, k_] := SeriesCoefficient[eta[x, k]^n, {x, 0, k}];
    Table[A[n - k, k], {n, 0, 11}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Nov 10 2018 *)
  • Sage
    from sage.modular.etaproducts import qexp_eta
    def A319933row(n, len):
        return (qexp_eta(ZZ['q'], len+4)^n).list()[:len]
    for n in (0..10):
        print(A319933row(n, 10))
    

A360400 a(n) = A356133(A360392(n)).

Original entry on oeis.org

7, 13, 20, 22, 29, 32, 34, 40, 47, 49, 53, 58, 62, 67, 74, 76, 83, 85, 89, 94, 97, 104, 110, 112, 115, 122, 127, 131, 137, 140, 142, 148, 155, 157, 161, 166, 169, 176, 182, 184, 187, 193, 200, 202, 208, 211, 215, 220, 223, 229, 236, 238, 244, 247, 251, 257
Offset: 1

Views

Author

Clark Kimberling, Mar 11 2023

Keywords

Comments

This is the third of four sequences that partition the positive integers. Suppose that u = (u(n)) and v = (v(n)) are increasing sequences of positive integers. Let u' and v' be their (increasing) complements, and consider these four sequences:
(1) u o v, defined by (u o v)(n) = u(v(n));
(2) u o v';
(3) u' o v;
(4) v' o u'.
Every positive integer is in exactly one of the four sequences. Their limiting densities are 4/9, 2/9, 2/9, 1/9 (and likewise for A360394-A360397 and A360402-A360405).

Examples

			(1)  u o v = (5, 8, 10, 12, 15, 16, 18, 21, 24, 26, 27, 30, 31, 35, 37, 39, ...) = A360398
(2)  u o v' = (1, 3, 6, 9, 14, 19, 23, 28, 33, 36, 41, 46, 51, 54, 60, 63, 68, ...) = A360399
(3)  u' o v = (7, 13, 20, 22, 29, 32, 34, 40, 47, 49, 53, 58, 62, 67, 74, 76, ...) = A360400
(4)  u' o v' = (2, 4, 11, 17, 25, 38, 43, 56, 64, 71, 79, 92, 101, 106, 119, ...) = A360401
		

Crossrefs

Cf. A026530, A356133, A360392, A360393, A360398, A286354, A286356, A360394 (intersections instead of results of composition), A360402-A360405.

Programs

  • Mathematica
    z = 2000;
    u = Accumulate[1 + ThueMorse /@ Range[0, 600]]; (* A026430 *)
    u1 = Complement[Range[Max[u]], u];  (* A356133 *)
    v = u + 2;  (* A360392 *)
    v1 = Complement[Range[Max[v]], v];  (* A360393 *)
    zz = 100;
    Table[u[[v[[n]]]], {n, 1, zz}]    (* A360398 *)
    Table[u[[v1[[n]]]], {n, 1, zz}]   (* A360399 *)
    Table[u1[[v[[n]]]], {n, 1, zz}]   (* A360400 *)
    Table[u1[[v1[[n]]]], {n, 1, zz}]  (* A360401 *)

A010831 Expansion of Product_{k>=1} (1-x^k)^26.

Original entry on oeis.org

1, -26, 299, -1950, 7475, -13754, -12220, 132756, -276575, 0, 1010100, -1486030, -519961, 2486300, 829725, -2215486, -11643060, 18523050, 16317925, -42861650, 0, 11010090, 59644221, -5743400, -138219900
Offset: 0

Views

Author

Keywords

Examples

			1 - 26*x + 299*x^2 - 1950*x^3 + 7475*x^4 - 13754*x^5 - 12220*x^6 + 132756*x^7 + ...
		

References

  • Morris Newman, A table of the coefficients of the powers of eta(tau), Nederl. Akad. Wetensch. Proc. Ser. A. 59 = Indag. Math. 18 (1956), 204-216.

Crossrefs

Column k=26 of A286354.

Programs

  • Mathematica
    CoefficientList[Expand@ Product[(1 - x^k)^26, {k, 25}], x, 25] (* Michael De Vlieger, Jun 08 2016 *)

Formula

a(0) = 1, a(n) = -(26/n) * Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Aug 13 2023

A010839 Expansion of Product_{k >= 1} (1-x^k)^48.

Original entry on oeis.org

1, -48, 1080, -15040, 143820, -985824, 4857920, -16295040, 28412910, 38671600, -424520544, 1268350272, -1211937160, -4306546080, 18293091840, -23522231424, -26299018683, 137218594320, -150999182320, -134713340160
Offset: 0

Views

Author

Keywords

Examples

			1 - 48*x + 1080*x^2 - 15040*x^3 + 143820*x^4 - 985824*x^5 + 4857920*x^6 - 16295040*x^7 + ...
		

References

  • Morris Newman, A table of the coefficients of the powers of eta(tau), Nederl. Akad. Wetensch. Proc. Ser. A. 59 = Indag. Math. 18 (1956), 204-216.

Crossrefs

Column k=48 of A286354.
Cf. A000203, A082558, A126581, A282330 (E_8^3), A282332 (E_6*E_8*E_10 = E4*E_10^2), A290009, A290010.

Formula

Let b(q) be the determinant of the 3 X 3 Hankel matrix [E_4, E_6, E_8 ; E_6, E_8, E_10 ; E_8, E_10, E_12]. G.f. is -691*b(q)/(q^2*1728^2*250). - Seiichi Manyama, Jul 17 2017
a(n) = (A290010(n+2) - A290009(n+2) + 691*(A282330(n+2) - A282332(n+2)))/(1728^2*250). - Seiichi Manyama, Jul 19 2017
a(0) = 1, a(n) = -(48/n) * Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Aug 13 2023

A010830 Expansion of Product_{k>=1} (1-x^k)^25.

Original entry on oeis.org

1, -25, 275, -1700, 6050, -9405, -15550, 107525, -182875, -81675, 756655, -801550, -662975, 1220175, 1361350, -209440, -9601900, 8608900, 14889050, -19948500, -6262465, -7057550, 38788925, 19716425, -69119875, 23579969, -82427400, 98068850, 191984400
Offset: 0

Views

Author

Keywords

References

  • Morris Newman, A table of the coefficients of the powers of eta(tau). Nederl. Akad. Wetensch. Proc. Ser. A. 59 = Indag. Math. 18 (1956), 204-216.

Crossrefs

Column k=25 of A286354.
Cf. A000203.

Formula

a(0) = 1, a(n) = -(25/n) * Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Aug 13 2023

A010832 Expansion of Product_{k>=1} (1-x^k)^27.

Original entry on oeis.org

1, -27, 324, -2223, 9126, -19278, -5967, 159030, -399087, 151593, 1270971, -2500875, 74970, 4203522, -1004157, -4796037, -11750778, 32885190, 10452375, -77533092, 27104868, 43070625, 63798840, -69960267, -215939061, 236414349, -37046646, 237487433, 85921371
Offset: 0

Views

Author

Keywords

References

  • Newman, Morris; A table of the coefficients of the powers of eta(tau). Nederl. Akad. Wetensch. Proc. Ser. A. 59 = Indag. Math. 18 (1956), 204-216.

Crossrefs

Column k=27 of A286354.
Cf. A000203.

Formula

a(0) = 1, a(n) = -(27/n) * Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Aug 13 2023
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