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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A162411 Number of reduced words of length n in the Weyl group D_42.

Original entry on oeis.org

1, 42, 902, 13202, 148091, 1357468, 10587675, 72245074, 440091498, 2430433874, 12315996232, 57824666110, 253554446677, 1045266952884, 4073988274266, 15084671038416, 53281879968821, 180187334962466, 585265396834041
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162412 Number of reduced words of length n in the Weyl group D_43.

Original entry on oeis.org

1, 43, 945, 14147, 162238, 1519706, 12107381, 84352455, 524443953, 2954877827, 15270874059, 73095540169, 326649986846, 1371916939730, 5445905213996, 20530576252412, 73812456221233, 253999791183699, 839265188017740
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162413 Number of reduced words of length n in the Weyl group D_44.

Original entry on oeis.org

1, 44, 989, 15136, 177374, 1697080, 13804461, 98156916, 622600869, 3577478696, 18848352755, 91943892924, 418593879770, 1790510819500, 7236416033496, 27766992285908, 101579448507141, 355579239690840, 1194844427708580
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162418 Number of reduced words of length n in the Weyl group D_45.

Original entry on oeis.org

1, 45, 1034, 16170, 193544, 1890624, 15695085, 113852001, 736452870, 4313931566, 23162284321, 115106177245, 533700057015, 2324210876515, 9560626910011, 37327619195919, 138907067703060, 494486307393900, 1689330735102480
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162452 Number of reduced words of length n in the Weyl group D_46.

Original entry on oeis.org

1, 46, 1080, 17250, 210794, 2101418, 17796503, 131648504, 868101374, 5182032940, 28344317261, 143450494506, 677150551521, 3001361428036, 12561988338047, 49889607533966, 188796675237026, 683282982630926, 2372613717733406
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162456 Number of reduced words of length n in the Weyl group D_47.

Original entry on oeis.org

1, 47, 1127, 18377, 229171, 2330589, 20127092, 151775596, 1019876970, 6201909910, 34546227171, 177996721677, 855147273198, 3856508701234, 16418497039281, 66308104573247, 255104779810273, 938387762441199
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162461 Number of reduced words of length n in the Weyl group D_48.

Original entry on oeis.org

1, 48, 1175, 19552, 248723, 2579312, 22706404, 174482000, 1194358970, 7396268880, 41942496051, 219939217728, 1075086490926, 4931595192160, 21350092231441, 87658196804688, 342762976614961, 1281150739056160
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162469 Number of reduced words of length n in the Weyl group D_49.

Original entry on oeis.org

1, 49, 1224, 20776, 269499, 2848811, 25555215, 200037215, 1394396185, 8790665065, 50733161116, 270672378844, 1345758869770, 6277354061930, 27627446293371, 115285643098059, 458048619713020, 1739199358769180
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A162492 Number of reduced words of length n in the Weyl group D_50.

Original entry on oeis.org

1, 50, 1274, 22050, 291549, 3140360, 28695575, 228732790, 1623128975, 10413794040, 61146955156, 331819334000, 1677578203770, 7954932265700, 35582378559071, 150868021657130, 608916641370150, 2348116000139330
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Dec 01 2009

Keywords

Comments

Computed with MAGMA using commands similar to those used to compute A161409.

References

  • N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche IV.)
  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.

Crossrefs

Formula

G.f. for D_m is the polynomial f(n) * Product( f(2i), i=1..n-1 )/ f(1)^n, where f(k) = 1-x^k. Only finitely many terms are nonzero. This is a row of the triangle in A162206.

A161696 Number of reduced words of length n in the Weyl group B_3.

Original entry on oeis.org

1, 3, 5, 7, 8, 8, 7, 5, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 0

Views

Author

John Cannon and N. J. A. Sloane, Nov 30 2009

Keywords

Comments

If the zeros are ignored, this is the coordination sequence for the truncated cuboctahedron (see the Karzes link). - N. J. A. Sloane, Jan 08 2020
Computed with MAGMA using commands similar to those used to compute A161409.

References

  • J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
  • N. Bourbaki, Groupes et algèbres de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)

Crossrefs

The growth series for the finite Coxeter (or Weyl) groups B_2 through B_12 are A161696-A161699, A161716, A161717, A161733, A161755, A161776, A161858. These are all rows of A128084. The growth series for the affine Coxeter (or Weyl) groups B_2 through B_12 are A008576, A008137, A267167-A267175.

Programs

  • Magma
    m:=10; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((&*[1-t^(2*k): k in [1..3]])/(1-t)^3)); // G. C. Greubel, Oct 25 2018
  • Maple
    seq(coeff(series(mul((1-x^(2k))/(1-x),k=1..3),x,n+1), x, n), n = 0 .. 120); # Muniru A Asiru, Oct 25 2018
  • Mathematica
    CoefficientList[Series[Product[(1-x^(2*k)), {k,1,3}] /(1-x)^3, {x,0,9}], x] (* G. C. Greubel, Oct 25 2018 *)
  • PARI
    t='t+O('t^10); Vec(prod(k=1,3,1-t^(2*k))/(1-t)^3) \\ G. C. Greubel, Oct 25 2018
    

Formula

G.f. for B_m is the polynomial Prod_{k=1..m}(1-x^(2k))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.
Previous Showing 11-20 of 120 results. Next