A077802
Sum of products of parts increased by 1 in hook partitions of n, where hook partitions are of the form h*1^(n-h).
Original entry on oeis.org
1, 2, 7, 18, 41, 88, 183, 374, 757, 1524, 3059, 6130, 12273, 24560, 49135, 98286, 196589, 393196, 786411, 1572842, 3145705, 6291432, 12582887, 25165798, 50331621, 100663268, 201326563, 402653154, 805306337, 1610612704
Offset: 0
The hook partitions of 4 are 4, 3+1, 2+1+1, 1+1+1+1; the corresponding products when parts are increased by 1 are 5, 8, 12, 16; and their sum is a(4) = 41.
A265836
Expansion of Product_{k>=1} 1/(1 - k*(k+1)*x^k).
Original entry on oeis.org
1, 2, 10, 32, 120, 342, 1206, 3320, 10604, 29578, 88342, 239400, 702020, 1863654, 5262650, 13948824, 38427192, 100244162, 272822282, 703972024, 1883948848, 4839944150, 12779850278, 32548367784, 85335644100, 215826029018, 560407835934, 1412632075328
Offset: 0
-
b:= proc(n, i) option remember; `if`(n=0 or i=1,
2^n, b(n, i-1)+(1+i)*i*b(n-i, min(n-i, i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..33); # Alois P. Heinz, Aug 16 2019
-
nmax = 40; CoefficientList[Series[Product[1/(1 - k*(k+1)*x^k), {k, 1, nmax}], {x, 0, nmax}], x]
A267008
Expansion of Product_{k>=1} (1 + (k+1)*x^k).
Original entry on oeis.org
1, 2, 3, 10, 13, 28, 58, 90, 146, 260, 481, 688, 1168, 1748, 2863, 4726, 6938, 10412, 16140, 23746, 35702, 55812, 79032, 116758, 168779, 247006, 350310, 513410, 744286, 1045466, 1485685, 2098780, 2935416, 4137878, 5746618, 8027612, 11343706, 15487222, 21418682
Offset: 0
-
b:= proc(n, i) option remember; `if`(i*(i+1)/2 b(n$2):
seq(a(n), n=0..42); # Alois P. Heinz, Aug 15 2019
-
nmax = 50; CoefficientList[Series[Product[1+(k+1)*x^k, {k, 1, nmax}], {x, 0, nmax}], x]
nmax = 50; poly = ConstantArray[0, nmax+1]; poly[[1]] = 1; poly[[2]] = 2; Do[Do[poly[[j+1]] += (k+1)*poly[[j-k+1]], {j, nmax, k, -1}];, {k, 2, nmax}]; poly
A079308
For a partition P of a positive integer, let f(P) be the product of k+1, over all parts k in P. Let a(n,r) be the sum of f(P) over all partitions P of n with smallest part r. Sequence gives table of a(n,r) for 1 <= r <= n, in the order a(1,1); a(2,1), a(2,2); a(3,1), a(3,2), a(3,3); ...
Original entry on oeis.org
2, 4, 3, 14, 0, 4, 36, 9, 0, 5, 100, 12, 0, 0, 6, 236, 42, 16, 0, 0, 7, 602, 54, 20, 0, 0, 0, 8, 1368, 195, 24, 25, 0, 0, 0, 9, 3242, 246, 92, 30, 0, 0, 0, 0, 10, 7240, 759, 112, 35, 36, 0, 0, 0, 0, 11, 16386, 1134, 232, 40, 42, 0, 0, 0, 0, 0, 12, 35692, 2859, 528, 170, 48, 49, 0, 0, 0, 0, 0, 13
Offset: 1
The partitions with minimal part 3 begin 3, 3+3, 4+3, 5+3, 6+3, 3+3+3, ... which yield the following values of f: 4, 16, 20, 24, 28, 64, ... therefore the 3rd column of our table begins 4,0,0,16,20,24,(28+64)=92,...
Triangle a(n,r) begins:
: 2;
: 4, 3;
: 14, 0, 4;
: 36, 9, 0, 5;
: 100, 12, 0, 0, 6;
: 236, 42, 16, 0, 0, 7;
: 602, 54, 20, 0, 0, 0, 8;
: 1368, 195, 24, 25, 0, 0, 0, 9;
: 3242, 246, 92, 30, 0, 0, 0, 0, 10;
: 7240, 759, 112, 35, 36, 0, 0, 0, 0, 11;
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b:= proc(n, k) option remember; `if`(n=0, 1,
`if`(k>n, 0, b(n, k+1) +(k+1)*b(n-k, k)))
end:
a:= (n, k)-> b(n,k)-b(n, k+1):
seq(seq(a(n, k), k=1..n), n=1..12); # Alois P. Heinz, May 22 2015
-
a[n_, r_] := Which[r>n, 0, r==n, n+1, True, a[n, r]=(r+1)Sum[a[n-r, s], {s, r, n-r}]]; Flatten[Table[a[n, r], {n, 1, 12}, {r, 1, n}]]
A078436
Triangle read by rows in which n-th row counts multisets associated with hook partitions.
Original entry on oeis.org
1, 2, 0, 3, 4, 0, 4, 6, 8, 0, 5, 8, 12, 16, 0, 6, 10, 16, 24, 32, 0, 7, 12, 20, 32, 48, 64, 0, 8, 14, 24, 40, 64, 96, 128, 0, 9, 16, 28, 48, 80, 128, 192, 256, 0, 10, 18, 32, 56, 96, 160, 256, 384, 512, 0, 11, 20, 36, 64, 112, 192, 320, 512, 768, 1024, 0, 12, 22, 40, 72, 128
Offset: 1
Triangle begins 1; 2,0; 3,4,0; 4,6,8,0; 5,8,12,16,0; ...
a(13) = 12 because we find 1 + 3 + 4 + 3 + 1 multisets of type 21^(n-2): they are 4; 14,24,34; 114,124,134,234; 1124,1134,1234; and 11234
A079274
Number of divisors associated with the cyclic cases within the n-th group of least prime signatures.
Original entry on oeis.org
1, 0, 3, 4, 14, 18, 65, 82, 253, 378, 953, 1460, 3667, 5480, 12917, 20582, 45130, 71970, 156510, 248020, 524446, 846962, 1733252, 2806484, 5702101, 9186010, 18375867, 29872508, 58760991, 95500008, 186871472, 302966474, 587603027, 956192230
Offset: 0
The number of divisors doubles each time we create a new "matching" partition by appending "1" to a given partition. Therefore we may write
..1..0..3..4..14..18..65..82..253..378..953...
+ ...2..4.14..36.100.236.602.1368.3242.7240...
= 1..2..7.18..50.118.301.684.1621.3620.8193...
More terms from Pab Ter (pabrlos(AT)yahoo.com), May 27 2004
A319110
Expansion of Product_{k>=1} 1/(1 - (k - 1)*x^k).
Original entry on oeis.org
1, 0, 1, 2, 4, 6, 13, 18, 37, 56, 101, 152, 285, 410, 713, 1118, 1830, 2780, 4618, 6934, 11278, 17092, 26894, 40822, 64435, 96372, 149299, 225104, 345131, 515394, 788176, 1169962, 1772957, 2632458, 3950365, 5849260, 8748993, 12867848, 19135894, 28126614, 41598695
Offset: 0
-
b:= proc(n, i) option remember; `if`(n=0 or i=1,
0^n, b(n, i-1)+(i-1)*b(n-i, min(n-i, i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..42); # Alois P. Heinz, Aug 19 2019
-
nmax = 40; CoefficientList[Series[Product[1/(1 - (k - 1) x^k), {k, 1, nmax}], {x, 0, nmax}], x]
nmax = 40; CoefficientList[Series[Exp[Sum[Sum[(j - 1)^k x^(j k)/k, {j, 1, nmax}], {k, 1, nmax}]], {x, 0, nmax}], x]
a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d (d - 1)^(k/d), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 40}]
A368090
Triangle read by rows. T(n, k) = Sum_{p in P(n, k)} Product_{r in p}(r + 1), where P(n, k) are the partitions of n with length k.
Original entry on oeis.org
1, 0, 2, 0, 3, 4, 0, 4, 6, 8, 0, 5, 17, 12, 16, 0, 6, 22, 34, 24, 32, 0, 7, 43, 71, 68, 48, 64, 0, 8, 52, 122, 142, 136, 96, 128, 0, 9, 86, 197, 325, 284, 272, 192, 256, 0, 10, 100, 350, 502, 650, 568, 544, 384, 512
Offset: 0
Triangle T(n, k) starts:
[0] [1]
[1] [0, 2]
[2] [0, 3, 4]
[3] [0, 4, 6, 8]
[4] [0, 5, 17, 12, 16]
[5] [0, 6, 22, 34, 24, 32]
[6] [0, 7, 43, 71, 68, 48, 64]
[7] [0, 8, 52, 122, 142, 136, 96, 128]
[8] [0, 9, 86, 197, 325, 284, 272, 192, 256]
[9] [0, 10, 100, 350, 502, 650, 568, 544, 384, 512]
-
def T(n, k):
return sum(product(r+1 for r in p) for p in Partitions(n, length=k))
for n in range(10): print([T(n, k) for k in range(n + 1)])
A368091
Triangle read by rows. T(n, k) = Sum_{p in P(n, k)} Product_{r in p} r, where P(n, k) are the partitions of n with length k.
Original entry on oeis.org
1, 0, 1, 0, 2, 1, 0, 3, 2, 1, 0, 4, 7, 2, 1, 0, 5, 10, 7, 2, 1, 0, 6, 22, 18, 7, 2, 1, 0, 7, 28, 34, 18, 7, 2, 1, 0, 8, 50, 62, 50, 18, 7, 2, 1, 0, 9, 60, 121, 86, 50, 18, 7, 2, 1, 0, 10, 95, 182, 189, 118, 50, 18, 7, 2, 1
Offset: 0
Table T(n, k) starts:
[0] [1]
[1] [0, 1]
[2] [0, 2, 1]
[3] [0, 3, 2, 1]
[4] [0, 4, 7, 2, 1]
[5] [0, 5, 10, 7, 2, 1]
[6] [0, 6, 22, 18, 7, 2, 1]
[7] [0, 7, 28, 34, 18, 7, 2, 1]
[8] [0, 8, 50, 62, 50, 18, 7, 2, 1]
[9] [0, 9, 60, 121, 86, 50, 18, 7, 2, 1]
-
def T(n, k):
return sum(product(r for r in p) for p in Partitions(n, length=k))
for n in range(10): print([T(n, k) for k in range(n + 1)])
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