A388969 Number of symmetric planar subpartitions of the size n pyramidal planar partition.

1, 2, 5, 24, 152, 1830, 29733, 914156, 38387059, 3042483506, 331741743716, 68163523131274, 19359648377444501, 10350309195733351734, 7674306266338654196695, 10702951402709865052445494, 20751102765963515996077429085, 75633429306024492094630275924556, 383922206968291957763420187246009609

Offset

0,2

Comments

The planar partition having its subpartitions counted is:

n n-1 ... 2 1

n-1 n-2 ... 1

... ...

2 1

1

A planar partition is said to be symmetric if it is equal to its transpose.

The number of all subpartitions regardless of symmetry is given by A115965.

Links

Table of n, a(n) for n=0..18.

Ludovic Schwob, Python Program

Prog

(Python) # See Links

Crossrefs

Cf. A005987, A049505, A115965.

Sequence in context: A054131 A086635 A020124 * A012249 A303108 A331035

Adjacent sequences: A388966 A388967 A388968 * A388970 A388971 A388972

Keyword

nonn

Author

Ludovic Schwob, Jan 24 2026

Status

approved