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Search: a182844 -id:a182844
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a(n) = A002865(2*n-1)+A002865(2*n).
+10
3
1, 3, 6, 11, 20, 35, 58, 96, 154, 242, 375, 573, 861, 1282, 1886, 2745, 3961, 5667, 8038, 11323, 15836, 22001, 30383, 41715, 56953, 77363, 104566, 140668, 188397, 251247, 333689, 441474, 581890, 764215, 1000233, 1304815, 1696717, 2199591, 2843073, 3664312
OFFSET
1,2
COMMENTS
a(n) is also the length of the n-th "large mirror" of the "mirror" version of the shell model of partitions of A135010.
LINKS
EXAMPLE
a(1)=0+1=1. a(2)=1+2=3: a(3)=2+4=6. a(4)=4+7=11. a(5)=8+12=20. a(6)=14+21=35.
CROSSREFS
Cf. A000041, A002865, A135010. For another version see A182844.
KEYWORD
nonn,easy
AUTHOR
Omar E. Pol, Jan 24 2011
EXTENSIONS
Extended by Nathaniel Johnston, May 06 2011
STATUS
approved
Irregular triangle read by rows: T(n,k), n >= 0, k >= 1, in which if n is even then row n lists the first A008619(n) even indexed terms of A027336 otherwise if n is odd then row n lists the first A008619(n) odd indexed terms of A027336.
+10
0
1, 1, 1, 1, 1, 2, 1, 1, 3, 1, 2, 4, 1, 1, 3, 6, 1, 2, 4, 8, 1, 1, 3, 6, 11, 1, 2, 4, 8, 15, 1, 1, 3, 6, 11, 20, 1, 2, 4, 8, 15, 26, 1, 1, 3, 6, 11, 20, 35, 1, 2, 4, 8, 15, 26, 45, 1, 1, 3, 6, 11, 20, 35, 58, 1, 2, 4, 8, 15, 26, 45, 75, 1, 1, 3, 6, 11, 20, 35, 58, 96, 1, 2, 4, 8, 15, 26, 45, 75, 121
OFFSET
0,6
COMMENTS
The sum of row n equals the number of partitions of n.
EXAMPLE
Triangle begins:
1;
1;
1, 1;
1, 2;
1, 1, 3;
1, 2, 4;
1, 1, 3, 6;
1, 2, 4, 8;
1, 1, 3, 6, 11;
1, 2, 4, 8, 15;
1, 1, 3, 6, 11, 20;
1, 2, 4, 8, 15, 26;
1, 1, 3, 6, 11, 20, 35;
1, 2, 4, 8, 15, 26, 45;
1, 1, 3, 6, 11, 20, 35, 58;
1, 2, 4, 8, 15, 26, 45, 75;
1, 1, 3, 6, 11, 20, 35, 58, 96;
1, 2, 4, 8, 15, 26, 45, 75, 121;
...
For n = 10 the sum of the 10th row is 1 + 1 + 3 + 6 + 11 + 20 = 42, the same as the number of partitions of 10.
CROSSREFS
Row sums give A000041.
Row lengths give A008619.
Right border gives A027336.
Columns 1..4: A000012, A000034, A010702, A010724.
KEYWORD
nonn,tabf
AUTHOR
Omar E. Pol, Aug 01 2024
STATUS
approved

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