A357140 Number of n X n triangular (0,1)-matrices with exactly 2n entries equal to 1 and no zero rows or columns.

1, 0, 0, 1, 26, 865, 39268, 2375965, 185974145, 18337523130, 2227232055239, 327003956573263, 57121908284696448, 11712143532463633752, 2786114854266411595229, 761208643373263480081077, 236761580851204534640426709, 83183218467008383189955036015

Offset

0,5

Links

Table of n, a(n) for n=0..17.

Formula

a(n) = A137252(2n,n).

Crossrefs

Cf. A137252.

Sequence in context: A160140 A139670 A231282 * A333117 A263945 A335609

Adjacent sequences: A357137 A357138 A357139 * A357141 A357142 A357143

Keyword

nonn

Author

Alois P. Heinz, Sep 14 2022

Status

approved