A347843 a(n) is the number of (strict) chains of subspaces with ends 0 and (F_5)^n.

1, 7, 249, 44643, 40065301, 179833594207, 4036127700341649, 452932494435315724443, 254139954749268142006053901, 712988623255130761190069046824407, 10001434425838325885839124865408303623049

Offset

1,2

Links

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

Formula

a(n) = Sum_{L partition of n} A347488(n, L) * A036038(len(L), sig(L)), where sig(L) is the partition composed by the part multiplicities of L.

Example

a(3) = 249 = 1 * 1 + 31 * 2 + 186 * 1, counting:
the unrefined chain 0 < (F_5)^3;
31 chains 0 < V < (F_5)^3, with dim(V) = 1; another
31 chains 0 < V < (F_5)^3, with dim(V) = 2; and
186 chains 0 < V_1 < V_2 < (F_5)^3.

Crossrefs

Cf. A289545, A347488, A036038.

Sequence in context: A203698 A229482 A193371 * A338633 A142805 A203474

Adjacent sequences: A347840 A347841 A347842 * A347844 A347845 A347846

Keyword

nonn

Author

Álvar Ibeas, Sep 15 2021

Status

approved