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.

Previous Showing 21-26 of 26 results.

A266780 Molien series for invariants of finite Coxeter group A_11.

Original entry on oeis.org

1, 0, 1, 1, 2, 2, 4, 4, 7, 8, 12, 14, 21, 23, 33, 39, 52, 61, 81, 94, 122, 143, 180, 211, 264, 306, 377, 440, 533, 619, 746, 861, 1028, 1186, 1401, 1612, 1895, 2168, 2532, 2894, 3356, 3822, 4414, 5008, 5755, 6516, 7448, 8410, 9580, 10780, 12232, 13737, 15524, 17388, 19592, 21885, 24580, 27400, 30674, 34117, 38097, 42269, 47074, 52133
Offset: 0

Views

Author

N. J. A. Sloane, Jan 11 2016

Keywords

Comments

The Molien series for the finite Coxeter group of type A_k (k >= 1) has g.f. = 1/Product_{i=2..k+1} (1 - x^i).
Note that this is the root system A_k, not the alternating group Alt_k.

References

  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.

Crossrefs

Molien series for finite Coxeter groups A_1 through A_12 are A059841, A103221, A266755, A008667, A037145, A001996, and A266776-A266781.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 70); Coefficients(R!( 1/(&*[1-x^j: j in [2..12]]) )); // G. C. Greubel, Feb 04 2020
    
  • Maple
    S:=series(1/mul(1-x^j, j=2..12)), x, 75):
    seq(coeff(S, x, j), j=0..70); # G. C. Greubel, Feb 04 2020
  • Mathematica
    CoefficientList[Series[1/Times@@(1-t^Range[2,12]),{t,0,70}],t] (* Harvey P. Dale, Jun 20 2017 *)
  • PARI
    Vec( 1/prod(j=2,12, 1-x^j) +O('x^70) ) \\ G. C. Greubel, Feb 04 2020
    
  • Sage
    def A266780_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1/prod(1-x^j for j in (2..12)) ).list()
    A266780_list(70) # G. C. Greubel, Feb 04 2020

Formula

G.f.: 1/((1-t^2)*(1-t^3)*(1-t^4)*(1-t^5)*(1-t^6)*(1-t^7)*(1-t^8)*(1-t^9)*(1-t^10)*(1-t^11)*(1-t^12)).

A266772 Molien series for invariants of finite Coxeter group D_9.

Original entry on oeis.org

1, 0, 1, 0, 2, 0, 3, 0, 5, 1, 7, 1, 11, 2, 15, 3, 22, 5, 30, 7, 41, 11, 54, 15, 73, 22, 94, 30, 123, 41, 157, 54, 201, 73, 252, 94, 318, 123, 393, 157, 488, 201, 598, 252, 732, 318, 887, 393, 1076, 488, 1291, 598, 1549, 732, 1845, 887, 2194, 1076, 2592, 1291, 3060, 1549, 3589, 1845, 4206, 2194, 4904, 2592, 5708, 3060, 6615, 3589
Offset: 0

Views

Author

N. J. A. Sloane, Jan 11 2016

Keywords

Comments

The Molien series for the finite Coxeter group of type D_k (k >= 3) has G.f. = 1/Prod_i (1-x^(1+m_i)) where the m_i are [1,3,5,...,2k-3,k-1]. If k is even only even powers of x appear, and we bisect the sequence.

References

  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.

Crossrefs

Molien series for finite Coxeter groups D_3 through D_12 are A266755, A266769, A266768, A003402, and A266770-A266775.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 80); Coefficients(R!( 1/((1-x^9)*(&*[1-x^(2*j): j in [1..8]])) )); // G. C. Greubel, Feb 03 2020
    
  • Maple
    seq(coeff(series(1/((1-x^9)*mul(1-x^(2*j), j=1..8)), x, n+1), x, n), n = 0..80); # G. C. Greubel, Feb 03 2020
  • Mathematica
    CoefficientList[Series[1/((1-x^9)*Product[1-x^(2*j), {j,8}]), {x,0,80}], x] (* G. C. Greubel, Feb 03 2020 *)
  • PARI
    Vec(1/((1-x^9)*prod(j=1,8,1-x^(2*j))) +O('x^80)) \\ G. C. Greubel, Feb 03 2020
    
  • Sage
    def A266772_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1/((1-x^9)*product(1-x^(2*j) for j in (1..8))) ).list()
    A266772_list(80) # G. C. Greubel, Feb 03 2020

Formula

G.f.: 1/((1-t^2)*(1-t^4)*(1-t^6)*(1-t^8)*(1-t^9)*(1-t^10)*(1-t^12)*(1-t^14)*(1-t^16)).

A266773 Molien series for invariants of finite Coxeter group D_10 (bisected).

Original entry on oeis.org

1, 1, 2, 3, 5, 8, 12, 17, 25, 35, 49, 66, 90, 119, 158, 206, 267, 342, 437, 551, 694, 865, 1074, 1324, 1627, 1985, 2414, 2919, 3518, 4219, 5045, 6003, 7125, 8422, 9927, 11660, 13660, 15949, 18578, 21575, 24998, 28884, 33303, 38298, 43955, 50329, 57513, 65581, 74645, 84786
Offset: 0

Views

Author

N. J. A. Sloane, Jan 11 2016

Keywords

Comments

The Molien series for the finite Coxeter group of type D_k (k >= 3) has G.f. = 1/Prod_i (1-x^(1+m_i)) where the m_i are [1,3,5,...,2k-3,k-1]. If k is even only even powers of x appear, and we bisect the sequence.

References

  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.

Crossrefs

Molien series for finite Coxeter groups D_3 through D_12 are A266755, A266769, A266768, A003402, and A266770-A266775.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/((1-x^5)*(&*[1-x^j: j in [1..9]])) )); // G. C. Greubel, Feb 03 2020
    
  • Maple
    seq(coeff(series(1/((1-x^5)*mul(1-x^j, j=1..9)), x, n+1), x, n), n = 0..50); # G. C. Greubel, Feb 03 2020
  • Mathematica
    CoefficientList[Series[1/((1-x^5)*Product[1-x^j, {j,9}]), {x,0,50}], x] (* G. C. Greubel, Feb 03 2020 *)
  • PARI
    Vec(1/((1-x^5)*prod(j=1,9,1-x^j)) +O('x^50)) \\ G. C. Greubel, Feb 03 2020
    
  • Sage
    def A266773_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1/((1-x^5)*product(1-x^j for j in (1..9))) ).list()
    A266773_list(50) # G. C. Greubel, Feb 03 2020

Formula

G.f.: 1/((1-t^2)*(1-t^4)*(1-t^6)*(1-t^8)*(1-t^10)^2*(1-t^12)*(1-t^14)*(1-t^16)*(1-t^18)), bisected.
G.f.: 1/( (1-x^5)*(Product_{j=1..9} 1-x^j) ). - G. C. Greubel, Feb 03 2020

A266774 Molien series for invariants of finite Coxeter group D_11.

Original entry on oeis.org

1, 0, 1, 0, 2, 0, 3, 0, 5, 0, 7, 1, 11, 1, 15, 2, 22, 3, 30, 5, 42, 7, 56, 11, 76, 15, 99, 22, 131, 30, 169, 42, 219, 56, 278, 76, 355, 99, 445, 131, 560, 169, 695, 219, 863, 278, 1060, 355, 1303, 445, 1586, 560, 1930, 695, 2331, 863, 2812, 1060, 3370, 1303, 4035, 1586, 4802, 1930, 5708, 2331, 6751, 2812, 7972, 3370, 9373, 4035, 11004
Offset: 0

Views

Author

N. J. A. Sloane, Jan 11 2016

Keywords

Comments

The Molien series for the finite Coxeter group of type D_k (k >= 3) has G.f. = 1/Prod_i (1-x^(1+m_i)) where the m_i are [1,3,5,...,2k-3,k-1]. If k is even only even powers of x appear, and we bisect the sequence.

References

  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.

Crossrefs

Molien series for finite Coxeter groups D_3 through D_12 are A266755, A266769, A266768, A003402, and A266770-A266775.

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 80); Coefficients(R!( 1/((1-x^11)*(&*[1-x^(2*j): j in [1..10]])) )); // G. C. Greubel, Feb 03 2020
    
  • Maple
    seq(coeff(series(1/((1-x^11)*mul(1-x^(2*j), j=1..10)), x, n+1), x, n), n = 0..80); # G. C. Greubel, Feb 03 2020
  • Mathematica
    CoefficientList[Series[1/((1-x^11)*Product[1-x^(2*j), {j,10}]), {x,0,80}], x] (* G. C. Greubel, Feb 03 2020 *)
  • PARI
    Vec(1/((1-x^11)*prod(j=1,10,1-x^(2*j))) +O('x^80)) \\ G. C. Greubel, Feb 03 2020
    
  • Sage
    def A266774_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1/((1-x^11)*product(1-x^(2*j) for j in (1..10))) ).list()
    A266774_list(80) # G. C. Greubel, Feb 03 2020

Formula

G.f.: 1/((1-t^2)*(1-t^4)*(1-t^6)*(1-t^8)*(1-t^10)*(1-t^11)*(1-t^12)*(1-t^14)*(1-t^16)*(1-t^18)*(1-t^20)).

A333925 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of Product_{j=2..k+1} 1/(1 - x^j).

Original entry on oeis.org

1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 2, 1, 1, 0, 1, 0, 1, 1, 2, 1, 2, 0, 0, 1, 0, 1, 1, 2, 2, 3, 1, 1, 0, 1, 0, 1, 1, 2, 2, 3, 2, 2, 0, 0, 1, 0, 1, 1, 2, 2, 4, 3, 4, 2, 1, 0, 1, 0, 1, 1, 2, 2, 4, 3, 5, 3, 2, 0, 0, 1, 0, 1, 1, 2, 2, 4, 4, 6, 5, 5, 2, 1, 0
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 10 2020

Keywords

Comments

A(n,k) is the number of partitions of n into parts 2, 3, ..., k and k + 1.

Examples

			Square array begins:
  1,  1,  1,  1,  1,  1,  ...
  0,  0,  0,  0,  0,  0,  ...
  0,  1,  1,  1,  1,  1,  ...
  0,  0,  1,  1,  1,  1,  ...
  0,  1,  1,  2,  2,  2,  ...
  0,  0,  1,  1,  2,  2,  ...
		

Crossrefs

Main diagonal gives A002865.

Programs

  • Mathematica
    Table[Function[k, SeriesCoefficient[Product[1/(1 - x^j), {j, 2, k + 1}], {x, 0, n}]][i - n], {i, 0, 13}, {n, 0, i}] // Flatten

Formula

G.f. of column k: Product_{j=2..k+1} 1/(1 - x^j).

A266771 Molien series for invariants of finite Coxeter group D_8 (bisected).

Original entry on oeis.org

1, 1, 2, 3, 6, 8, 13, 18, 27, 36, 51, 67, 92, 118, 156, 198, 256, 319, 404, 498, 620, 755, 926, 1116, 1353, 1615, 1935, 2291, 2720, 3194, 3759, 4384, 5120, 5932, 6879, 7923, 9131, 10458, 11981, 13654, 15561, 17648, 20014, 22600, 25514, 28692, 32255, 36134, 40464, 45167
Offset: 0

Views

Author

N. J. A. Sloane, Jan 10 2016

Keywords

Comments

The Molien series for the finite Coxeter group of type D_k (k >= 3) has G.f. = 1/Prod_i (1-x^(1+m_i)) where the m_i are [1,3,5,...,2k-3,k-1]. If k is even only even powers of x appear, and we bisect the sequence.

References

  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.

Crossrefs

Molien series for finite Coxeter groups D_3 through D_12 are A266755, A266769, A266768, A003402, and A266770-A266775.

Programs

  • Mathematica
    Take[CoefficientList[Series[1/((1-x^8)Times@@(1-x^Range[2,14,2])),{x,0,100}],x],{1,-1,2}] (* Harvey P. Dale, Jan 02 2018 *)

Formula

G.f.: 1/((1-t^8)^2*(1-t^2)*(1-t^4)*(1-t^6)*(1-t^10)*(1-t^12)*(1-t^14)), bisected.
Previous Showing 21-26 of 26 results.