A325472 Numbers having at least two representations as multinomial coefficients M(n;lambda), where lambda is a partition of n.

1, 6, 10, 12, 15, 20, 21, 24, 28, 30, 35, 36, 42, 45, 55, 56, 60, 66, 70, 72, 78, 84, 90, 91, 105, 110, 120, 126, 132, 136, 140, 153, 156, 165, 168, 171, 180, 182, 190, 210, 220, 231, 240, 252, 253, 272, 276, 280, 286, 300, 306, 325, 330, 336, 342, 351, 360

Offset

1,2

Comments

Numbers that are repeated in the triangle A036038 (all positive integers occur at least once).

All triangular numbers (A000217) except 0 and 3 are in this sequence.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..20000

Wikipedia, Multinomial coefficients

Wikipedia, Partition (number theory)

Formula

a(n) = A305188(n-1) for n > 1.

Example

1 is in the sequence because M(0;0) = M(1;1) = M(2;2) = M(3;3) = ... = 1.
6 is in the sequence because M(6;5,1) = M(4;2,2) = M(3;1,1,1) = 6.
42 is in the sequence because M(42;41,1) = M(7;5,1,1) = 42.

Crossrefs

Cf. A000041, A000217, A036038, A305188, A325306, A325593, A325901.

Sequence in context: A143958 A294278 A297366 * A305188 A359201 A270364

Adjacent sequences: A325469 A325470 A325471 * A325473 A325474 A325475

Keyword

nonn

Author

Alois P. Heinz, Sep 06 2019

Status

approved