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A325472
Numbers having at least two representations as multinomial coefficients M(n;lambda), where lambda is a partition of n.
9
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.
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.
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 06 2019
STATUS
approved