Original entry on oeis.org
1, 1, 4, 365, 3086331, 5612271711927, 3829797188212731601783, 1478967550753025951356611840021161, 452501475882033837823819972299248189399008553836, 146630849220097180917463638217405949960396188742877031073909770851
Offset: 0
-
b:= proc(n, k) option remember; `if`(n=0, 1, add(
binomial(k*n-1, k*j-1)*b(n-j, k), j=1..n))
end:
a:= n-> b(n$2):
seq(a(n), n=0..10); # Alois P. Heinz, Aug 14 2019
-
b[n_, k_] := b[n, k] = If[n == 0, 1, Sum[Binomial[k n - 1, k j - 1] b[n - j, k], {j, 1, n}]];
a[n_] := b[n, n];
a /@ Range[0, 10] (* Jean-François Alcover, Nov 07 2020, after Maple *)
A260878
Number of set partitions of {1, 2, ..., 2*n} with sizes in {[n, n], [2n]}.
Original entry on oeis.org
2, 2, 4, 11, 36, 127, 463, 1717, 6436, 24311, 92379, 352717, 1352079, 5200301, 20058301, 77558761, 300540196, 1166803111, 4537567651, 17672631901, 68923264411, 269128937221, 1052049481861, 4116715363801, 16123801841551, 63205303218877, 247959266474053
Offset: 0
The set partitions counted by a(3) = 11 are: {{1, 2, 3, 4, 5, 6}},
{{1, 2, 4}, {3, 5, 6}}, {{1, 2, 3}, {4, 5, 6}}, {{1, 3, 4}, {2, 5, 6}},
{{1, 3, 5}, {2, 4, 6}}, {{1, 4, 5}, {2, 3, 6}}, {{1, 5, 6}, {2, 3, 4}},
{{1, 4, 6}, {2, 3, 5}}, {{1, 3, 6}, {2, 4, 5}}, {{1, 2, 6}, {3, 4, 5}},
{{1, 2, 5}, {3, 4, 6}}.
a(n+1) - a(n) =
A097613(n+1) for n > 0.
-
a := proc(n) option remember;
if n < 2 then [2, 2][n+1] else ((4*n - 2)*a(n-1) - 3*n + 2)/n fi end:
seq(a(n), n=0..26); # Or:
egf := n -> exp(exp(x)*(1 - (GAMMA(n,x)/GAMMA(n)))):
a := n -> `if`(n<2, 2, (2*n)!*coeff(series(egf(n), x, 2*n+1), x, 2*n)):
seq(a(n), n=0..26); # Peter Luschny, Aug 02 2019
-
Table[Binomial[2 n - 1, n] + 1, {n, 0, 26}] (* or *)
CoefficientList[Series[(4 x^2 - 13 x + 3 + Sqrt[(1 - 4 x) (x - 1)^2])/(2 (4 x - 1) (x - 1)), {x, 0, 26}], x] (* Michael De Vlieger, Feb 26 2017 *)
-
print([A260876(n,2) for n in (0..30)])
-
# Alternative:
def A260878():
a, f, s, n = 2, 2, 1, 1
yield a
while True:
yield a
f += 4; s += 3; n += 1
a = (f*a - s)/n
a = A260878()
print([next(a) for n in range(27)]) # Peter Luschny, Aug 02 2019
A327001
Generalized Bell numbers, square array read by ascending antidiagonals, A(n, k) for n, k >= 0.
Original entry on oeis.org
1, 1, 1, 1, 1, 2, 1, 1, 2, 4, 1, 1, 4, 5, 8, 1, 1, 11, 31, 15, 16, 1, 1, 36, 365, 379, 52, 32, 1, 1, 127, 6271, 25323, 6556, 203, 64, 1, 1, 463, 129130, 3086331, 3068521, 150349, 877, 128, 1, 1, 1717, 2877421, 512251515, 3309362716, 583027547, 4373461, 4140, 256
Offset: 0
[n\k][0 1 2 3 4 5 6]
[ - ] -----------------------------------------------------
[ 0 ] 1, 1, 2, 4, 8, 16, 32 A011782
[ 1 ] 1, 1, 2, 5, 15, 52, 203 A000110
[ 2 ] 1, 1, 4, 31, 379, 6556, 150349 A005046
[ 3 ] 1, 1, 11, 365, 25323, 3068521, 583027547 A291973
[ 4 ] 1, 1, 36, 6271, 3086331, 3309362716, 6626013560301 A291975
A260878, A326998,
Formatted as a triangle:
[1]
[1, 1]
[1, 1, 2]
[1, 1, 2, 4]
[1, 1, 4, 5, 8]
[1, 1, 11, 31, 15, 16]
[1, 1, 36, 365, 379, 52, 32]
[1, 1, 127, 6271, 25323, 6556, 203, 64]
-
A327001 := proc(n, k) option remember; if k = 0 then return 1 fi;
add(binomial(n*k - 1, n*j) * A327001(n, j), j = 0..k-1) end:
for n from 0 to 6 do seq(A327001(n, k), k=0..6) od; # row-wise
-
A[n_, k_] := A[n, k] = If[k == 0, 1, Sum[Binomial[n*k-1, n*j]*A[n, j], {j, 0, k-1}]];
Table[A[n-k, k], {n, 0, 9}, {k, 0, n}] // Flatten (* Jean-François Alcover, Sep 27 2022 *)
A260875
Square array read by ascending antidiagonals: number of m-shape complementary Bell numbers.
Original entry on oeis.org
1, 1, -1, 1, -1, 0, 1, -1, 0, -1, 1, -1, 2, 1, 1, 1, -1, 9, -1, 1, -1, 1, -1, 34, -197, -43, -2, 1, 1, -1, 125, -5281, 6841, 254, -9, -1, 1, -1, 461, -123124, 2185429, -254801, 4157, -9, 2, 1, -1, 1715, -2840293, 465693001, -1854147586, -3000807, -70981, 50, -2
Offset: 1
[ n ] [ 0 1 2 3 4 5 6]
[ m ] --------------------------------------------------------
[ 0 ] [ 1, -1, 0, -1, 1, -1, 1] A081362
[ 1 ] [ 1, -1, 0, 1, 1, -2, -9] A000587
[ 2 ] [ 1, -1, 2, -1, -43, 254, 4157] A260884
[ 3 ] [ 1, -1, 9, -197, 6841, -254801, -3000807]
[ 4 ] [ 1, -1, 34, -5281, 2185429, -1854147586, 2755045819549]
A010763,
For example the number of set partitions of {1,2,...,9} with sizes in [9], [6,3] and [3,3,3] are 1, 84, 280 respectively. Thus A(3,3) = -1 + 84 - 280 = -197.
Formatted as a triangle:
[1]
[1, -1]
[1, -1, 0]
[1, -1, 0, -1]
[1, -1, 2, 1, 1]
[1, -1, 9, -1, 1, -1]
[1, -1, 34, -197, -43, -2, 1]
[1, -1, 125, -5281, 6841, 254, -9, -1]
-
def A260875(m, n):
shapes = ([x*m for x in p] for p in Partitions(n))
return sum((-1)^len(s)*SetPartitions(sum(s),s).cardinality() for s in shapes)
for m in (0..4): print([A260875(m,n) for n in (0..6)])
A260883
Number of m-shape ordered set partitions, square array read by ascending antidiagonals, A(m, n) for m, n >= 0.
Original entry on oeis.org
1, 1, 1, 1, 1, 3, 1, 1, 3, 9, 1, 1, 7, 13, 35, 1, 1, 21, 121, 75, 161, 1, 1, 71, 1849, 3907, 541, 913, 1, 1, 253, 35641, 426405, 202741, 4683, 6103, 1, 1, 925, 762763, 65782211, 203374081, 15430207, 47293, 47319, 1, 1, 3433, 17190265, 11872636325, 323213457781, 173959321557
Offset: 1
[ n ] [0 1 2 3 4 5 6]
[ m ] -----------------------------------------------------------
[ 0 ] [1, 1, 3, 9, 35, 161, 913] A101880
[ 1 ] [1, 1, 3, 13, 75, 541, 4683] A000670
[ 2 ] [1, 1, 7, 121, 3907, 202741, 15430207] A094088
[ 3 ] [1, 1, 21, 1849, 426405, 203374081, 173959321557] A243664
[ 4 ] [1, 1, 71, 35641, 65782211, 323213457781, 3482943541940351] A243665
A244174
For example the number of ordered set partitions of {1,2,...,9} with sizes in [9], [6,3] and [3,3,3] is 1, 168 and 1680 respectively. Thus A(3,3) = 1849.
Formatted as a triangle:
[1]
[1, 1]
[1, 1, 3]
[1, 1, 3, 9]
[1, 1, 7, 13, 35]
[1, 1, 21, 121, 75, 161]
[1, 1, 71, 1849, 3907, 541, 913]
[1, 1, 253, 35641, 426405, 202741, 4683, 6103]
-
def A260883(m, n):
shapes = ([x*m for x in p] for p in Partitions(n))
return sum(factorial(len(s))*SetPartitions(sum(s), s).cardinality() for s in shapes)
for m in (0..4): print([A260883(m, n) for n in (0..6)])
A260877
Square array read by ascending antidiagonals: number of m-shape Euler numbers.
Original entry on oeis.org
1, 1, -1, 1, -1, 1, 1, -1, 1, -5, 1, -1, 5, -1, 21, 1, -1, 19, -61, 1, -105, 1, -1, 69, -1513, 1385, -1, 635, 1, -1, 251, -33661, 315523, -50521, 1, -4507, 1, -1, 923, -750751, 60376809, -136085041, 2702765, -1, 36457, 1, -1, 3431, -17116009, 11593285251
Offset: 1
[ n ] [0 1 2 3 4 5 6]
[ m ] --------------------------------------------------------------
[ 0 ] [1, -1, 1, -5, 21, -105, 635] A260845
[ 1 ] [1, -1, 1, -1, 1, -1, 1] A033999
[ 2 ] [1, -1, 5, -61, 1385, -50521, 2702765] A028296
[ 3 ] [1, -1, 19, -1513, 315523, -136085041, 105261234643] A002115
[ 4 ] [1, -1, 69, -33661, 60376809, -288294050521, 3019098162602349] A211212
A030662,A211213, A181991,
For example the number of ordered set partitions of {1,2,...,9} with sizes in [9], [6,3] and [3,3,3] are 1, 168, 1680 respectively. Thus A(3,3) = -1 + 168 - 1680 = -1513.
Formatted as a triangle:
[1]
[1, -1]
[1, -1, 1]
[1, -1, 1, -5]
[1, -1, 5, -1, 21]
[1, -1, 19, -61, 1, -105]
[1, -1, 69, -1513, 1385, -1, 635]
Cf.
A002115,
A028296,
A030662,
A033999,
A181991,
A211212,
A211213,
A260845,
A260833,
A260875,
A260876.
-
def A260877(m,n):
shapes = ([x*m for x in p] for p in Partitions(n).list())
return sum((-1)^len(s)*factorial(len(s))*SetPartitions(sum(s), s). cardinality() for s in shapes)
for m in (0..5): print([A260877(m,n) for n in (0..7)])
A309522
Generalized Blasius numbers, square array read by ascending antidiagonals, A(n, k) for n, k >= 0.
Original entry on oeis.org
1, 1, 1, 1, 1, 2, 1, 1, 2, 5, 1, 1, 4, 6, 14, 1, 1, 11, 34, 24, 42, 1, 1, 36, 375, 496, 120, 132, 1, 1, 127, 6306, 27897, 11056, 720, 429, 1, 1, 463, 129256, 3156336, 3817137, 349504, 5040, 1430, 1, 1, 1717, 2877883, 514334274, 3501788976, 865874115, 14873104, 40320, 4862
Offset: 0
Table A(n,k) (with rows n >= 0 and columns k >= 0) begins as follows:
[0] 1, 1, 2, 5, 14, 42, 132, ... A000108
[1] 1, 1, 2, 6, 24, 120, 720, ... A000142
[2] 1, 1, 4, 34, 496, 11056, 349504, ... A002105
[3] 1, 1, 11, 375, 27897, 3817137, 865874115, ... A018893
[4] 1, 1, 36, 6306, 3156336, 3501788976, 7425169747776, ...
A260878|
- Heinrich Blasius, Grenzschichten in Flüssigkeiten mit kleiner Reibung, Z. Math. u. Physik 56 (1908), 1-37; see p. 8. [This article was based on his PhD thesis. He corrected c_6 = A(n=3, k=6) but his "correction" of c_7 = A(n=3, k=7) was not right!]
- Heinrich Blasius, Grenzschichten in Flüssigkeiten mit kleiner Reibung, Z. Math. u. Physik 56 (1908), 1-37 [English translation by J. Vanier on behalf of the National Advisory Committee for Aeronautics (NACA), 1950]; see p. 8. [This is a translation of Blasius' article. The value of c_6 = A(n=3, k=6) was corrected in the article and the translation, but the "correction" for c_7 = A(n=3, k=7) in both documents is wrong.]
- Markus Kuba and Alois Panholzer, Combinatorial families of multilabelled increasing trees and hook-length formulas, arXiv:1411.4587 [math.CO], 2014.
- Markus Kuba and Alois Panholzer, Combinatorial families of multilabelled increasing trees and hook-length formulas, Discrete Mathematics 339(1) (2016), 227-254.
- Hans Salié, Über die Koeffizienten der Blasiusschen Reihen, Math. Nachr. 14 (1955), 241-248 (1956). [In the article the array is denoted by c^{(n)}_v for n, v >= 1. We have A(n, k) = c^{(n)}_{k+1} for n >= 1 and k >= 0. The Catalan numbers (row n = 0 for A(n, k)) do not appear in Salié's article.]
-
A := proc(n, k) option remember; if k = 0 then 1 else
add(binomial(n*k-1, n*v)*A(n, v)*A(n, k-1-v), v=0..k-1) fi end:
seq(seq(A(n-k, k), k=0..n), n=0..9);
-
A[n_, k_] := A[n, k] = If[k == 0, 1, Sum[Binomial[n*k - 1, n*v]*A[n, v]* A[n, k - 1 - v], {v, 0, k - 1}]];
Table[A[n - k, k], {n, 0, 9}, {k, 0, n}] // Flatten (* Jean-François Alcover, Sep 26 2019, from Maple *)
A309725
Number of set partitions of {1,2,...,3n} with sizes in {[n, n, n], [2n, n], [3n]}.
Original entry on oeis.org
3, 5, 31, 365, 6271, 129130, 2877421, 66628441, 1578320767, 37983592076, 925196176906, 22754692780561, 564123212097901, 14079691134569845, 353428830512017081, 8915830309096530865, 225890912989184760703, 5744976464242932324976, 146603288011226858621356
Offset: 0
A327003
Irregular triangle read by rows in which the n-th row lists multinomials for partitions of 3n which have only parts which are multiples of 3, in Hindenburg order.
Original entry on oeis.org
1, 1, 1, 10, 1, 84, 280, 1, 220, 462, 9240, 15400, 1, 455, 5005, 50050, 210210, 1401400, 1401400, 1, 816, 18564, 185640, 24310, 4084080, 13613600, 2858856, 85765680, 285885600, 190590400, 1, 1330, 54264, 542640, 293930, 24690120, 82300400, 32332300, 135795660, 2715913200, 4526522000, 3802278480, 38022784800, 76045569600, 36212176000
Offset: 0
The irregular triangle starts:
[0] [1]
[1] [1]
[2] [1, 10]
[3] [1, 84, 280]
[4] [1, 220, 462, 9240, 15400]
[5] [1, 455, 5005, 50050, 210210, 1401400, 1401400]
[6] [1, 816, 18564, 185640, 24310, 4084080, 13613600, 2858856, 85765680, 285885600, 190590400]
A327004
Irregular triangle read by rows in which the n-th row lists multinomials for partitions of 4n which have only parts which are multiples of 4, in Hindenburg order.
Original entry on oeis.org
1, 1, 1, 35, 1, 495, 5775, 1, 1820, 6435, 450450, 2627625, 1, 4845, 125970, 4408950, 31177575, 727476750, 2546168625, 1, 10626, 735471, 25741485, 1352078, 1338557220, 15616500900, 1577585295, 165646455975, 1932541986375, 4509264634875
Offset: 0
The irregular triangle starts:
[0] [1]
[1] [1]
[2] [1, 35]
[3] [1, 495, 5775]
[4] [1, 1820, 6435, 450450, 2627625]
[5] [1, 4845, 125970, 4408950, 31177575, 727476750, 2546168625]
[6] [1, 10626, 735471, 25741485, 1352078, 1338557220, 15616500900, 1577585295, 165646455975, 1932541986375, 4509264634875]
Showing 1-10 of 10 results.
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