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A360240
Weakly decreasing triples of positive integers sorted lexicographically and concatenated.
1
1, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 2, 3, 1, 1, 3, 2, 1, 3, 2, 2, 3, 3, 1, 3, 3, 2, 3, 3, 3, 4, 1, 1, 4, 2, 1, 4, 2, 2, 4, 3, 1, 4, 3, 2, 4, 3, 3, 4, 4, 1, 4, 4, 2, 4, 4, 3, 4, 4, 4, 5, 1, 1, 5, 2, 1, 5, 2, 2, 5, 3, 1, 5, 3, 2, 5, 3, 3, 5, 4, 1, 5, 4, 2, 5, 4, 3
OFFSET
1,4
FORMULA
a(n) = A331195(n-1) + 1.
EXAMPLE
Triples begin: (1,1,1), (2,1,1), (2,2,1), (2,2,2), (3,1,1), (3,2,1), (3,2,2), (3,3,1), (3,3,2), (3,3,3), ...
MATHEMATICA
nn=9; Join@@Select[Tuples[Range[nn], 3], GreaterEqual@@#&]
CROSSREFS
The triples have sums A070770.
Positions of first appearances are A158842.
For pairs instead of triples we have A330709 + 1.
The zero-based version is A331195.
- The first part is A360010 = A056556 + 1.
- The second part is A194848 = A056557 + 1.
- The third part is A333516 = A056558 + 1.
Sequence in context: A008679 A029435 A089643 * A185090 A115268 A103610
KEYWORD
nonn
AUTHOR
Gus Wiseman, Feb 11 2023
STATUS
approved