Nick Mayers - cp's OEIS frontend

A319982 a(n) is the number of integer partitions of n with largest part <= 4 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

1, 1, 1, 2, 3, 2, 3, 3, 4, 3, 3, 2, 4, 2, 3, 1, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0, 4, 2, 3, 0

Offset: 1

Nick Mayers, Oct 03 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n) is periodic with period 4 for n > 16.

Colin Barker, Table of n, a(n) for n = 1..1000
V. Coll, A. Mayers, N. Mayers, Statistics on integer partitions arising from seaweed algebras, arXiv preprint arXiv:1809.09271 [math.CO], 2018.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1).

Cf. A319981, A320033, A320034, A320036.

Join[{1, 1, 1, 2, 3, 2, 3, 3, 4, 3, 3, 2, 4, 2, 3, 1}, LinearRecurrence[{0, 0, 0, 1}, {4, 2, 3, 0}, 100]] (* Jean-François Alcover, Dec 07 2018 *)

Vec(x*(1 + x + x^2 + 2*x^3 + 2*x^4 + x^5 + 2*x^6 + x^7 + x^8 + x^9 - x^11 - x^13 - x^15 - x^19) / ((1 - x)*(1 + x)*(1 + x^2)) + O(x^100)) \\ Colin Barker, Apr 21 2019

For n > 16: a(n)=4 if 1 == n (mod 4), a(n)=2 if 2 == n (mod 4), a(n)=3 if 3 == n (mod 4), a(n)=0 if 0 == n (mod 4).
From Colin Barker, Apr 21 2019: (Start)
G.f.: x*(1 + x + x^2 + 2*x^3 + 2*x^4 + x^5 + 2*x^6 + x^7 + x^8 + x^9 - x^11 - x^13 - x^15 - x^19) / ((1 - x)*(1 + x)*(1 + x^2)).
a(n) = a(n-4) for n>20.
(End)

A320033 a(n) is the number of integer partitions of n with largest part <= 5 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

Original entry on oeis.org

1, 1, 1, 2, 3, 3, 4, 5, 6, 6, 4, 6, 7, 5, 5, 6, 7, 4, 5, 5, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3, 7, 3, 5, 3

Offset: 1

Nick Mayers, Oct 03 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n) is periodic with period 4 for n > 20.

Colin Barker, Table of n, a(n) for n = 1..1000
V. Coll, A. Mayers, N. Mayers, Statistics on integer partitions arising from seaweed algebras, arXiv preprint arXiv:1809.09271 [math.CO], 2018.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1).

Cf. A319981, A319982, A320034, A320036.

Join[{1, 1, 1, 2, 3, 3, 4, 5, 6, 6, 4, 6, 7, 5, 5, 6, 7, 4, 5, 5}, LinearRecurrence[{0, 0, 0, 1}, {7, 3, 5, 3}, 100]] (* Jean-François Alcover, Dec 07 2018 *)

Vec(x*(1 + x + x^2 + 2*x^3 + 2*x^4 + 2*x^5 + 3*x^6 + 3*x^7 + 3*x^8 + 3*x^9 + x^11 + x^12 - x^13 + x^14 - x^17 - x^19 - x^21 - 2*x^23) / ((1 - x)*(1 + x)*(1 + x^2)) + O(x^100)) \\ Colin Barker, Apr 21 2019

For n > 20: a(n)=7 if 1 == n (mod 4), a(n)=3 if 2 == n (mod 4), a(n)=5 if 3 == n (mod 4), a(n)=3 if 0 == n (mod 4).
From Colin Barker, Apr 21 2019: (Start)
G.f.: x*(1 + x + x^2 + 2*x^3 + 2*x^4 + 2*x^5 + 3*x^6 + 3*x^7 + 3*x^8 + 3*x^9 + x^11 + x^12 - x^13 + x^14 - x^17 - x^19 - x^21 - 2*x^23) / ((1 - x)*(1 + x)*(1 + x^2)).
a(n) = a(n-4) for n>24.
(End)

A320034 a(n) is the number of integer partitions of n with largest part <= 6 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

Original entry on oeis.org

1, 1, 1, 2, 3, 3, 5, 6, 7, 7, 6, 9, 11, 8, 8, 9, 11, 9, 11, 9, 12, 9, 8, 9, 14, 6, 9, 5, 11, 6, 11, 4, 12, 5, 8, 4, 14, 5, 9, 3, 11, 5, 11, 3, 12, 5, 8, 3, 14, 5, 9, 3, 11, 5, 11, 3, 12, 5, 8, 3, 14, 5, 9, 3, 11, 5, 11, 3, 12, 5, 8, 3, 14, 5, 9, 3, 11, 5, 11, 3, 12, 5, 8, 3, 14, 5, 9, 3, 11, 5, 11, 3, 12, 5, 8, 3

Offset: 1

Nick Mayers, Oct 03 2018

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]), where [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n) is periodic with period 12 for n > 36.

Colin Barker, Table of n, a(n) for n = 1..1000
V. Coll, A. Mayers, N. Mayers, Statistics on integer partitions arising from seaweed algebras, arXiv preprint arXiv:1809.09271 [math.CO], 2018.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.
Index entries for linear recurrences with constant coefficients, signature (0,-1,0,0,0,1,0,1).

Cf. A319981, A319982, A320033, A320036.

a[n_] := If[n <= 36, {1, 1, 1, 2, 3, 3, 5, 6, 7, 7, 6, 9, 11, 8, 8, 9, 11, 9, 11, 9, 12, 9, 8, 9, 14, 6, 9, 5, 11, 6, 11, 4, 12, 5, 8, 4}[[n]], Switch[ Mod[n, 12], 1, 14, 2|6|10, 5, 3, 9, 0|4|8, 3, 5|7, 11, 9, 12, 11, 8]]; Array[a, 100] (* Jean-François Alcover, Dec 08 2018 *)

Vec(x*(1 + x + 2*x^2 + 3*x^3 + 4*x^4 + 5*x^5 + 7*x^6 + 8*x^7 + 10*x^8 + 10*x^9 + 9*x^10 + 11*x^11 + 9*x^12 + 8*x^13 + 7*x^14 + 4*x^15 + 6*x^16 + 2*x^17 + 5*x^18 + x^19 + 4*x^20 + x^21 + x^22 - 3*x^25 - 7*x^27 - 7*x^29 - 5*x^31 - 2*x^33 - 2*x^35 - x^37 - x^39 - x^41 - x^43) / ((1 - x)*(1 + x)*(1 - x + x^2)*(1 + x^2)*(1 + x + x^2)) + O(x^100)) \\ Colin Barker, Apr 21 2019

For n > 36: a(n)=14 if 1 == n (mod 12), a(n)=5 if 2,6,10 == n (mod 12), a(n)=9 if 3 == n (mod 12), a(n)=3 if 0,4,8 == n (mod 12), a(n)=11 if 5,7 == n (mod 12), a(n)=12 if 9 == n (mod 12), a(n)=8 if 11 == n (mod 12).

G.f.: x*(1 + x + 2*x^2 + 3*x^3 + 4*x^4 + 5*x^5 + 7*x^6 + 8*x^7 + 10*x^8 + 10*x^9 + 9*x^10 + 11*x^11 + 9*x^12 + 8*x^13 + 7*x^14 + 4*x^15 + 6*x^16 + 2*x^17 + 5*x^18 + x^19 + 4*x^20 + x^21 + x^22 - 3*x^25 - 7*x^27 - 7*x^29 - 5*x^31 - 2*x^33 - 2*x^35 - x^37 - x^39 - x^41 - x^43) / ((1 - x)*(1 + x)*(1 - x + x^2)*(1 + x^2)*(1 + x + x^2)). - Colin Barker, Apr 21 2019

Data corrected by Jean-François Alcover, Dec 08 2018

A320036 a(n) is the number of integer partitions of n with largest part <= 7 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

Original entry on oeis.org

1, 1, 1, 2, 3, 3, 5, 7, 8, 8, 8, 12, 14, 13, 11, 16, 16, 16, 17, 18, 18, 20, 16, 21, 20, 19, 16, 17, 19, 15, 18, 15, 19, 12, 17, 14, 20, 11, 17, 10, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7, 19, 9, 18, 7, 19, 9, 17, 7, 20, 9, 17, 7

Offset: 1

Nick Mayers, Oct 03 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n) is periodic with period 12 for n > 40.

V. Coll, A. Mayers, N. Mayers, Statistics on integer partitions arising from seaweed algebras, arXiv preprint arXiv:1809.09271 [math.CO], 2018.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.
Index entries for linear recurrences with constant coefficients, signature (0, -1, 0, 0, 0, 1, 0, 1).

Cf. A319981, A319982, A320033, A320034.

a[n_] := If[n <= 40, {1, 1, 1, 2, 3, 3, 5, 7, 8, 8, 8, 12, 14, 13, 11, 16, 16, 16, 17, 18, 18, 20, 16, 21, 20, 19, 16, 17, 19, 15, 18, 15, 19, 12, 17, 14, 20, 11, 17, 10}[[n]], Switch[Mod[n, 12], 1|5|9, 7, 2, 20, 3|7|11, 9, 0|4, 17, 6|10, 19, 8, 18]]; Array[a, 125] (* Jean-François Alcover, Dec 08 2018 *)

For n > 40: a(n)=7 if 1,5,9 == n (mod 12), a(n)=20 if 2 == n (mod 12), a(n)=9 if 3,7,11 == n (mod 12), a(n)=17 if 0,4 == n (mod 12), a(n)=19 if 6,10 == n (mod 12), a(n)=18 if 8 == n (mod 12).

Missing term a(41)=7 inserted by Jean-François Alcover, Dec 08 2018

A319981 a(n) is the number of integer partitions of n with largest part <= 3 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2

Offset: 1

Nick Mayers, Oct 03 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n) is periodic with period 2 for n>12.

Muniru A Asiru, Table of n, a(n) for n = 1..1000
V. Coll, A. Mayers, N. Mayers, Statistics on integer partitions arising from seaweed algebras, arXiv preprint arXiv:1809.09271 [math.CO], 2018.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.
Index entries for linear recurrences with constant coefficients, signature (0, 1).

Cf. A319982, A320033, A320034, A320036

a:=[1,1,1,2,2,1,2,1,2,1,2,1,2];; Concatenation(a,Flat(List([1..30],n->[0,2]))); # Muniru A Asiru, Dec 07 2018

1,1,1,2,2,1,2,1,2,1,2,1,2 seq(op([0,2]),n=1..30); # Muniru A Asiru, Dec 07 2018

Join[{1, 1, 1, 2, 2, 1, 2, 1, 2, 1, 2, 1}, LinearRecurrence[{0, 1}, {2, 0}, 100]] (* Jean-François Alcover, Dec 07 2018 *)

For n>12: a(n)=2 if n is odd, a(n)=0 if n is even.

A318238 a(n) is the number of integer partitions of n for which the crank is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

Original entry on oeis.org

0, 0, 1, 1, 1, 1, 2, 2, 2, 3, 6, 5, 5, 8, 14, 15, 15, 24, 27, 38, 47, 58, 66, 83, 92, 118, 156, 187, 234, 262, 329, 367, 446, 517, 657, 712, 890, 1041, 1270, 1411, 1751, 1951, 2350, 2678, 3278, 3715

Offset: 1

Nick Mayers, Melissa Mayers, Aug 21 2018

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n)>0 for n>2. To see this: if n=k+1 take the partition (k,1).

V. Coll, M. Hyatt, C. Magnant, H. Wang, Meander graphs and Frobenius seaweed Lie algebras II, Journal of Generalized Lie Theory and Applications 9 (1) (2015) 227.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.

Cf. A237832, A318176, A318177, A318178, A318196, A318203

A318205 a(n) is the number of integer partitions of n for which the rank is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

Original entry on oeis.org

1, 1, 2, 1, 1, 2, 2, 5, 2, 7, 7, 6, 10, 12, 12, 16, 14, 22, 27, 28, 44, 52, 61, 76, 93, 112, 135, 162, 209, 243, 300, 350, 425, 484, 600, 662, 863, 964, 1153, 1351, 1629, 1874, 2244, 2584, 3074, 3507, 4213, 4805, 5725, 6524, 7742, 8770, 10357, 11813, 13936, 15704, 18445, 20896, 24552, 27724

Offset: 1

Nick Mayers, Aug 21 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n)>0 for n>0. To see this for n, take the partition (n).

V. Coll, M. Hyatt, C. Magnant, H. Wang, Meander graphs and Frobenius seaweed Lie algebras II, Journal of Generalized Lie Theory and Applications 9 (1) (2015) 227.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.

Cf. A237832, A318176, A318177, A318178, A318196

A318203 a(n) is the number of integer partitions of n for which the largest part is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

Original entry on oeis.org

0, 0, 1, 1, 0, 1, 1, 3, 3, 3, 5, 6, 6, 10, 13, 18, 18, 27, 31, 40, 52, 58, 78, 95, 103, 136, 161, 194, 225, 265, 346, 386, 483, 585, 660, 797, 938, 1134, 1316, 1521, 1832, 2081, 2550, 2901, 3407, 3913, 4614, 5345, 6305, 7280, 8514, 9824, 11377, 13120, 14960, 17427, 19981, 23316, 26859, 30390

Offset: 1

Nick Mayers, Melissa Mayers Aug 21 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n) > 0 for n = 3, 4 and n > 5. To see this: for n odd if n=3 take the partition (1,1,1), if n > 5 take the partition (2,...,2,1,1,1,1,1); for n > 2 congruent to 2 (mod 6), say n=6k+2, take the partition (2k,1,...,1) with 4k+2 1's; for n > 0 congruent to 4 (mod 6), say n=6k+4, take the partition (2k+1, 1,...,1) with 4k+3 1's; for n > 0 congruent to 0 (mod 6), say n=6k, take the partition (2k, 2k, 2k-1, 1).

V. Coll, M. Hyatt, C. Magnant, H. Wang, Meander graphs and Frobenius seaweed Lie algebras II, Journal of Generalized Lie Theory and Applications 9 (1) (2015) 227.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.

Cf. A237832, A318176, A318177, A318178, A318196

A318196 a(n) is the number of integer partitions of n for which the smallest part is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

Original entry on oeis.org

0, 0, 1, 1, 2, 2, 5, 4, 7, 7, 16, 11, 23, 22, 43, 41, 61, 56, 97, 103, 126, 146, 205, 210, 274, 315, 389, 461, 531, 623, 751, 901, 968, 1227, 1372, 1661, 1787, 2238, 2332, 2998, 3105, 3921, 4103, 5241, 5148, 6778, 6795, 8745, 8683, 11231, 11133, 14523, 14246, 18284, 18121, 23536, 22790, 29627, 29143, 36990

Offset: 1

Nick Mayers, Aug 20 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n)>0 for n>2. To see this: for n odd, say n=2k+3, take the partition (2k+1,1,1); for n even, say n=2k+4, take the partition (2k+1,1,1,1).

V. Coll, M. Hyatt, C. Magnant, H. Wang, Meander graphs and Frobenius seaweed Lie algebras II, Journal of Generalized Lie Theory and Applications 9 (1) (2015) 227.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.

Cf. A237832, A318176, A318177, A318178, A318203

A318178 a(n) is the number of integer partitions of n for which the length is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

Original entry on oeis.org

0, 1, 0, 0, 0, 2, 0, 0, 2, 2, 1, 2, 1, 8, 9, 5, 8, 15, 10, 17, 21, 24, 25, 45, 43, 68, 53, 82, 81, 143, 111, 165, 168, 247, 232, 314, 313, 442, 491, 587, 596, 918, 842, 1217, 1304, 1645, 1650, 2221, 2311, 2922, 3119, 4007, 4184, 5521, 5699, 7232, 7498, 9543, 9580, 12802

Offset: 1

Nick Mayers, Aug 20 2018

nonn

The index of a Lie algebra, g, is an invariant of the Lie algebra defined by min(dim(Ker(B_f)) where the min is taken over all linear functionals f on g and B_f denotes the bilinear form f([,]) were [,] denotes the bracket multiplication on g.
For seaweed subalgebras of sl(n), which are Lie subalgebras of sl(n) whose matrix representations are parametrized by an ordered pair of compositions of n, the index can be determined from a corresponding graph called a meander.
a(n)>0 for n=2,6 and n>8. To see this: for n congruent to 2,6 (mod 8) take the partition of the form (2,...,2); for n>=9 congruent to 1,5 (mod 8), say n=4k+1, take the partition (4k-3,3,1); for n>7 congruent to 3 (mod 8), say n=8k+3, take the partition (4k,3,2,...,2) with 2k 2's; for n>7 congruent to 7 (mod 8) take the partition ((n-1)/2, (n-5)/2,3); for n>8 congruent to 4 (mod 8) take the partition (n-8,4,3,1); and for n>8 congruent to 0 (mod 8) take the partition (n-8,4,4).

V. Coll, M. Hyatt, C. Magnant, H. Wang, Meander graphs and Frobenius seaweed Lie algebras II, Journal of Generalized Lie Theory and Applications 9 (1) (2015) 227.
V. Dergachev, A. Kirillov, Index of Lie algebras of seaweed type, J. Lie Theory 10 (2) (2000) 331-343.

Cf. A318176, A318177, A237832, A318196, A318203

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User: Nick Mayers

A319982 a(n) is the number of integer partitions of n with largest part <= 4 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

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A320033 a(n) is the number of integer partitions of n with largest part <= 5 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

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A320034 a(n) is the number of integer partitions of n with largest part <= 6 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

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A320036 a(n) is the number of integer partitions of n with largest part <= 7 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

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A319981 a(n) is the number of integer partitions of n with largest part <= 3 for which the index of the seaweed algebra formed by the integer partition paired with its weight is 0.

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A318238 a(n) is the number of integer partitions of n for which the crank is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

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A318205 a(n) is the number of integer partitions of n for which the rank is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

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Author

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A318203 a(n) is the number of integer partitions of n for which the largest part is equal to the index of the seaweed algebra formed by the integer partition paired with its weight.

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Author

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