A206283
Triangle read by rows: T(n,k) = sum of the k-th parts of all partitions of n with their parts written in nondecreasing order.
Original entry on oeis.org
1, 3, 1, 5, 3, 1, 9, 7, 3, 1, 12, 12, 7, 3, 1, 20, 21, 14, 7, 3, 1, 25, 31, 24, 14, 7, 3, 1, 38, 47, 40, 26, 14, 7, 3, 1, 49, 66, 61, 43, 26, 14, 7, 3, 1, 69, 93, 92, 70, 45, 26, 14, 7, 3, 1, 87, 124, 130, 106, 73, 45, 26, 14, 7, 3, 1
Offset: 1
Row 4 is 9, 7, 3, 1 because the five partitions of 4, with their parts written in nondecreasing order, are
. 4
. 1, 3
. 2, 2
. 1, 1, 2
. 1, 1, 1, 1
-------------------------------------------
And the sums of the columns are 9, 7, 3, 1.
.
Triangle begins:
1;
3, 1;
5, 3, 1;
9, 7, 3, 1;
12, 12, 7, 3, 1;
20, 21, 14, 7, 3, 1;
25, 31, 24, 14, 7, 3, 1;
38, 47, 40, 26, 14, 7, 3, 1;
49, 66, 61, 43, 26, 14, 7, 3, 1;
69, 93, 92, 70, 45, 26, 14, 7, 3, 1;
A207381
Total sum of the odd-indexed parts of all partitions of n.
Original entry on oeis.org
1, 3, 7, 14, 25, 45, 72, 117, 180, 275, 403, 596, 846, 1206, 1681, 2335, 3183, 4342, 5820, 7799, 10321, 13622, 17798, 23221, 30009, 38706, 49567, 63316, 80366, 101805, 128211, 161134, 201537, 251495, 312508, 387535, 478674, 590072, 724920, 888795, 1086324
Offset: 1
For n = 5, write the partitions of 5 and below write the sums of their odd-indexed parts:
. 5
. 3+2
. 4+1
. 2+2+1
. 3+1+1
. 2+1+1+1
. 1+1+1+1+1
. ------------
. 20 + 4 + 1 = 25
The total sum of the odd-indexed parts is 25 so a(5) = 25.
-
b:= proc(n, i) option remember; local g, h;
if n=0 then [1, 0$2]
elif i<1 then [0$3]
else g:= b(n, i-1); h:= `if`(i>n, [0$3], b(n-i, i));
[g[1]+h[1], g[2]+h[3], g[3]+h[2]+i*h[1]]
fi
end:
a:= n-> b(n,n)[3]:
seq(a(n), n=1..50); # Alois P. Heinz, Mar 12 2012
-
b[n_, i_] := b[n, i] = Module[{g, h}, If[n == 0 , {1, 0, 0}, If[i < 1, {0, 0, 0}, g = b[n, i - 1]; h = If[i > n, {0, 0, 0}, b[n - i, i]]; {g[[1]] + h[[1]], g[[2]] + h[[3]], g[[3]] + h[[2]] + i*h[[1]]}]]]; a[n_] := b[n, n][[3]]; Table [a[n], {n, 1, 50}] (* Jean-François Alcover, Dec 09 2016 after Alois P. Heinz *)
A207382
Sum of the even-indexed parts of all partitions of n.
Original entry on oeis.org
0, 1, 2, 6, 10, 21, 33, 59, 90, 145, 213, 328, 467, 684, 959, 1361, 1866, 2588, 3490, 4741, 6311, 8422, 11067, 14579, 18941, 24630, 31703, 40788, 52019, 66315, 83891, 106034, 133182, 167045, 208397, 259637, 321895, 398498, 491295, 604725, 741579, 908008
Offset: 1
For n = 5, write the partitions of 5 and below write the sums of their even-indexed parts:
. 5
. 3+2
. 4+1
. 2+2+1
. 3+1+1
. 2+1+1+1
. 1+1+1+1+1
------------
. 8 + 2 = 10
The sum of the even-indexed parts is 10, so a(5) = 10.
From _George Beck_, Apr 15 2017: (Start)
Alternatively, sum the floors of the parts divided by 2:
. 2
. 1+1
. 2+0
. 1+1+0
. 1+0+0
. 1+0+0+0
. 0+0+0+0+0
The sum is 10, so a(5) = 10. (End)
-
b:= proc(n, i) option remember; local g, h;
if n=0 then [1, 0$2]
elif i<1 then [0$3]
else g:= b(n, i-1); h:= `if`(i>n, [0$3], b(n-i, i));
[g[1]+h[1], g[2]+h[3], g[3]+h[2]+i*h[1]]
fi
end:
a:= n-> b(n,n)[2]:
seq (a(n), n=1..50); # Alois P. Heinz, Mar 12 2012
-
b[n_, i_] := b[n, i] = Module[{g, h}, Which[n==0, {1, 0, 0}, i<1, {0, 0, 0}, True, g = b[n, i-1]; h = If[i>n, {0, 0, 0}, b[n-i, i]]; {g[[1]] + h[[1]], g[[2]] + h[[3]], g[[3]] + h[[2]] + i*h[[1]]}]]; a[n_] := b[n, n][[2]]; Table [a[n], {n, 1, 50}] (* Jean-François Alcover, Feb 03 2017, after Alois P. Heinz *)
a[n_]:= Total@Flatten@Quotient[IntegerPartitions[n], 2];
Table [a[n], {n, 1, 50}] (* George Beck, Apr 15 2017 *)
A210950
Triangle read by rows: T(n,k) = number of parts in the k-th column of the partitions of n but with the partitions aligned to the right margin.
Original entry on oeis.org
1, 1, 2, 1, 2, 3, 1, 2, 4, 5, 1, 2, 4, 6, 7, 1, 2, 4, 7, 10, 11, 1, 2, 4, 7, 11, 14, 15, 1, 2, 4, 7, 12, 17, 21, 22, 1, 2, 4, 7, 12, 18, 25, 29, 30, 1, 2, 4, 7, 12, 19, 28, 36, 41, 42, 1, 2, 4, 7, 12, 19, 29, 40, 50, 55, 56, 1, 2, 4, 7, 12, 19, 30, 43
Offset: 1
For n = 6 the partitions of 6 aligned to the right margin look like this:
.
. 6
. 3 + 3
. 4 + 2
. 2 + 2 + 2
. 5 + 1
. 3 + 2 + 1
. 4 + 1 + 1
. 2 + 2 + 1 + 1
. 3 + 1 + 1 + 1
. 2 + 1 + 1 + 1 + 1
. 1 + 1 + 1 + 1 + 1 + 1
.
The number of parts in columns 1-6 are
. 1, 2, 4, 7, 10, 11, the same as the 6th row of triangle.
Triangle begins:
1;
1, 2;
1, 2, 3;
1, 2, 4, 5;
1, 2, 4, 6, 7;
1, 2, 4, 7, 10, 11;
1, 2, 4, 7, 11, 14, 15;
1, 2, 4, 7, 12, 17, 21, 22;
1, 2, 4, 7, 12, 18, 25, 29, 30;
1, 2, 4, 7, 12, 19, 28, 36, 41, 42;
1, 2, 4, 7, 12, 19, 29, 40, 50, 55, 56;
1, 2, 4, 7, 12, 19, 30, 43, 58, 70, 76, 77;
-
m[n_, k_] := Length[IntegerPartitions[n][[k]]]; c[n_] := PartitionsP[n];
t[n_, h_] := Select[Range[c[n]], m[n, #] == h &, 1];
Column[Table[t[n, h], {n, 1, 20}, {h, 1, n}]]
(* Clark Kimberling, Oct 16 2023 *)
A210951
Triangle read by rows: T(n,k) = number of parts in the k-th column of the shell model of partitions considering only the n-th shell and with its parts aligned to the right margin.
Original entry on oeis.org
1, 0, 2, 0, 0, 3, 0, 0, 1, 5, 0, 0, 0, 1, 7, 0, 0, 0, 1, 3, 11, 0, 0, 0, 0, 1, 3, 15, 0, 0, 0, 0, 1, 3, 6, 22, 0, 0, 0, 0, 0, 1, 4, 7, 30, 0, 0, 0, 0, 0, 1, 3, 7, 11, 42, 0, 0, 0, 0, 0, 0, 1, 4, 9, 13, 56, 0, 0, 0, 0, 0, 0, 1, 3, 8, 15, 20, 77, 0, 0, 0
Offset: 1
For n = 6 and k = 1..6 the 6th shell looks like this:
-------------------------
k: 1, 2, 3, 4, 5, 6
-------------------------
. 6
. 3 + 3
. 4 + 2
. 2 + 2 + 2
. 1
. 1
. 1
. 1
. 1
. 1
. 1
.
The total number of parts in columns 1-6 are
. 0, 0, 0, 1, 3, 11, the same as the 6th row of triangle.
Triangle begins:
1;
0, 2;
0, 0, 3;
0, 0, 1, 5;
0, 0, 0, 1, 7;
0, 0, 0, 1, 3, 11;
0, 0, 0, 0, 1, 3, 15;
0, 0, 0, 0, 1, 3, 6, 22;
0, 0, 0, 0, 0, 1, 4, 7, 30;
0, 0, 0, 0, 0, 1, 3, 7, 11, 42;
0, 0, 0, 0, 0, 0, 1, 4, 9, 13, 56;
0, 0, 0, 0, 0, 0, 1, 3, 8, 15, 20, 77;
A210946
Triangle read by rows: T(n,k) = sum of parts in the k-th column of the mirror of the last section of the set of partitions of n with its parts aligned to the right margin.
Original entry on oeis.org
1, 3, 5, 9, 2, 12, 3, 20, 9, 2, 25, 11, 3, 38, 22, 9, 2, 49, 28, 14, 3, 69, 44, 26, 9, 2, 87, 55, 37, 14, 3, 123, 83, 62, 29, 9, 2, 152
Offset: 1
For n = 7 the illustration shows two arrangements of the last section of the set of partitions of 7:
.
. (7) (7)
. (4+3) (3+4)
. (5+2) (2+5)
. (3+2+2) (2+2+3)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. (1) (1)
. ---------
. 25,11,3
.
The left hand picture shows the last section of 7 with its parts aligned to the right margin. In the right hand picture (the mirror) we can see that the sum of all parts of the columns 1..3 are 25, 11, 3 therefore row 7 lists 25, 11, 3.
Written as a triangle begins:
1;
3;
5;
9, 2;
12, 3;
20, 9, 2;
25, 11, 3;
38, 22, 9, 2;
49, 28, 14, 3;
69, 44, 26, 9, 2;
87, 55, 37, 14, 3,
123, 83, 62, 29, 9, 2;
Cf.
A135010,
A138121,
A182703,
A194714,
A196807,
A206437,
A207031,
A207034,
A207035,
A210945,
A210952,
A210953.
Showing 1-6 of 6 results.
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