A347842 a(n) is the number of (strict) chains of subspaces with ends 0 and (F_4)^n.

1, 6, 148, 14808, 5942608, 9546508128, 61355108818240, 1577381936031968640, 162213856617581098030336, 66726795842176170072717129216, 109792555585903911536355551233758208, 722612693482570097701467493432061846673408

Offset

1,2

Links

Álvar Ibeas, Table of n, a(n) for n = 1..40

Formula

a(n) = Sum_{L partition of n} A347487(n, L) * A036038(len(L), sig(L)), where sig(L) is the partition composed by the part multiplicities of L.

Example

a(3) = 148 = 1 * 1 + 21 * 2 + 105 * 1, counting:
the unrefined chain 0 < (F_4)^3;
21 chains 0 < V < (F_4)^3, with dim(V) = 1; another
21 chains 0 < V < (F_4)^3, with dim(V) = 2; and
105 chains 0 < V_1 < V_2 < (F_4)^3.

Crossrefs

Cf. A289545, A347487, A036038.

Sequence in context: A375780 A199226 A012791 * A264645 A089480 A056427

Adjacent sequences: A347839 A347840 A347841 * A347843 A347844 A347845

Keyword

nonn

Author

Álvar Ibeas, Sep 15 2021

Status

approved