

A325901


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


4



1, 10, 15, 21, 28, 35, 36, 45, 55, 56, 60, 66, 78, 84, 91, 105, 120, 126, 136, 153, 165, 168, 171, 190, 210, 220, 231, 252, 253, 276, 280, 286, 300, 325, 330, 351, 360, 364, 378, 406, 435, 455, 462, 465, 495, 496, 504, 528, 560, 561, 595, 630, 660, 666, 680
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

Numbers that are repeated in the triangle A309992 (all positive integers except 2 occur at least once).
All triangular numbers (A000217) except 0, 3 and 6 are in this sequence.
All terms are also contained in A325472.


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000
Wikipedia, Multinomial coefficients
Wikipedia, Partition (number theory)


EXAMPLE

1 is in the sequence because M(0;0) = M(1;1) = M(2;2) = M(3;3) = ... = 1.
10 is in the sequence because M(10;9,1) = M(5;3,2) = 10.
55 is in the sequence because M(55;54,1) = M(11;9,2) = 55.
105 is in the sequence because M(7;4,2,1) = M(15;13,2) = M(105;104,1) = 105.


CROSSREFS

Cf. A000009, A000217, A309992, A325472, A325903.
Sequence in context: A108614 A115708 A068992 * A098564 A168103 A322045
Adjacent sequences: A325898 A325899 A325900 * A325902 A325903 A325904


KEYWORD

nonn


AUTHOR

Alois P. Heinz, Sep 07 2019


STATUS

approved



