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 1-5 of 5 results.

A003038 Dimensions of split simple Lie algebras over any field of characteristic zero.

Original entry on oeis.org

3, 8, 10, 14, 15, 21, 24, 28, 35, 36, 45, 48, 52, 55, 63, 66, 78, 80, 91, 99, 105, 120, 133, 136, 143, 153, 168, 171, 190, 195, 210, 224, 231, 248, 253, 255, 276, 288, 300, 323, 325, 351, 360, 378, 399, 406, 435, 440, 465, 483, 496, 528, 561, 575, 595, 624, 630
Offset: 1

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Examples

			The Lie algebras in question and their dimensions are the following:
A_l: l(l+2), l >= 1,
B_l: l(2l+1), l >= 2,
C_l: l(2l+1), l >= 3,
D_l: l(2l-1), l >= 4,
G_2: 14, F_4: 52, E_6: 78, E_7: 133, E_8: 248.
		

References

  • Freeman J. Dyson, Missed opportunities, Bull. Amer. Math. Soc. 78 (1972), 635-652.
  • N. Jacobson, Lie Algebras. Wiley, NY, 1962; pp. 141-146.
  • I. G. Macdonald, Some conjectures for root systems, SIAM J. Math. Anal., 13 (1982), 988-1007.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Subsequences, apart from some initial terms: A000217, A000384, A005563, A014105.

Programs

  • Haskell
    import Data.Set (deleteFindMin, fromList, insert)
    a003038 n = a003038_list !! (n-1)
    a003038_list = f (fromList (3 : [14, 52, 78, 133, 248]))
       (drop 2 a005563_list) (drop 4 a000217_list) where
       f s (x:xs) (y:ys) = m : f (x `insert` (y `insert` s')) xs ys where
         (m, s') = deleteFindMin s
    -- Reinhard Zumkeller, Dec 16 2012
  • Maple
    M:=4200; M2:=M^2; sa:=[seq(l*(l+2),l=1..M)]; sb:=[seq(l*(2*l+1),l=2..M)]; sd:=[seq(l*(2*l-1),l=4..M)]; se:=[14,52,78,133,248]; s:=convert(sa,set) union convert(sb,set) union convert(sd,set) union convert(se,set); t:=convert(s,list); for i from 1 to nops(t) do if t[i] <= M2 then lprint(i,t[i]); fi; od:
  • Mathematica
    max = 26; sa = Table[ k*(k+2), {k, 1, max}]; sb = Table[ k*(2k+1), {k, 2, max}]; sd:= Table[ k*(2k-1), {k, 4, max}]; se = {14, 52, 78, 133, 248}; Select[ Union[sa, sb, sd, se], # <= max^2 &](* Jean-François Alcover, Nov 18 2011, after Maple *)

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 09 2004

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

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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

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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

A010827 Expansion of Product_{k>=1} (1 - x^k)^21.

Original entry on oeis.org

1, -21, 189, -910, 2205, -378, -13321, 33345, -10395, -86870, 122703, 46683, -98287, -264915, 96390, 1163064, -1113588, -1066527, 1042055, 536025, 2287467, -3603805, -1391733, 478170, -562555, 13742379, -7889805
Offset: 0

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Comments

If not n == 0 (mod 7) then a(n) == 0 (mod 7). The reverse is not true, e.g., a(14) = 96390 == (0 mod 7). See the Hardy reference, p. 165. - Wolfdieter Lang, Jan 28 2017

Examples

			G.f. = 1 - 21*x + 189*x^2 - 910*x^3 + 2205*x^4 - 378*x^5 - 13321*x^6 + 33345*x^7 + ...
		

References

  • G. H. Hardy, Ramanujan: twelve lectures on subjects suggested by his life and work, AMS Chelsea Publishing, Providence, Rhode Island, 2002, p. 165.
  • 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

Cf. A126581.

Programs

  • Mathematica
    CoefficientList[Expand@ Product[(1 - x^k)^21, {k, 27}], x, 27] (* Michael De Vlieger, Jun 08 2016 *)
    a[ n_] := SeriesCoefficient[ QPochhammer[ x]^21, {x, 0, n}]; (* Michael Somos, Jan 28 2017 *)
  • PARI
    {a(n) = if( n<0, 0, polcoeff( eta(x + x * O(x^n))^21, n))}; /* Michael Somos, Jan 28 2017 */

Formula

G.f.: Product_{k>0} (1 - x^k)^21.
a(0) = 1, a(n) = -(21/n)*Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Mar 27 2017
G.f.: exp(-21*Sum_{k>=1} x^k/(k*(1 - x^k))). - Ilya Gutkovskiy, Feb 05 2018

A010833 Expansion of Product_{k>=1} (1-x^k)^28.

Original entry on oeis.org

1, -28, 350, -2520, 11025, -26180, 4158, 184600, -554400, 401100, 1496964, -3920280, 1444625, 6224400, -4972350, -7121296, -8308965, 50796900, -8971200, -121968000, 94011435, 80598288, 20282500, -175228200
Offset: 0

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Examples

			1 - 28*x + 350*x^2 - 2520*x^3 + 11025*x^4 - 26180*x^5 + 4158*x^6 + 184600*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=28 of A286354.

Formula

a(0) = 1, a(n) = -(28/n) * Sum_{k=1..n} A000203(k)*a(n-k) for n > 0. - Seiichi Manyama, Aug 13 2023
Showing 1-5 of 5 results.