A136394
Triangle read by rows: T(n,k) is the number of permutations of an n-set having k cycles of size > 1 (0<=k<=floor(n/2)).
Original entry on oeis.org
1, 1, 1, 1, 1, 5, 1, 20, 3, 1, 84, 35, 1, 409, 295, 15, 1, 2365, 2359, 315, 1, 16064, 19670, 4480, 105, 1, 125664, 177078, 56672, 3465, 1, 1112073, 1738326, 703430, 74025, 945, 1, 10976173, 18607446, 8941790, 1346345, 45045, 1, 119481284, 216400569, 118685336
Offset: 0
Triangle (n,k) begins:
1;
1;
1, 1;
1, 5;
1, 20, 3;
1, 84, 35;
1, 409, 295, 15;
1, 2365, 2359, 315;
...
- Alois P. Heinz, Rows n = 0..200, flattened
- Jean-Luc Baril and Sergey Kirgizov, Transformation à la Foata for special kinds of descents and excedances, arXiv:2101.01928 [math.CO], 2021. See Theorem 2. p. 5.
- FindStat - Combinatorial Statistic Finder, The number of nontrivial cycles of a permutation pi in its cycle decomposition
- Bin Han, Jianxi Mao, and Jiang Zeng, Equidistributions around special kinds of descents and excedances, arXiv:2103.13092 [math.CO], 2021, see page 2.
Columns k=0-10 give:
A000012,
A006231,
A289950,
A289951,
A289952,
A289953,
A289954,
A289955,
A289956,
A289957,
A289958.
-
egf:= proc(k::nonnegint) option remember; x-> exp(x)* ((-x-ln(1-x))^k)/k! end; T:= (n,k)-> coeff(series(egf(k)(x), x=0, n+1), x, n) *n!; seq(seq(T(n,k), k=0..n/2), n=0..30); # Alois P. Heinz, Aug 14 2008
# second Maple program:
b:= proc(n) option remember; expand(`if`(n=0, 1, add(b(n-i)*
`if`(i>1, x, 1)*binomial(n-1, i-1)*(i-1)!, i=1..n)))
end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(n)):
seq(T(n), n=0..15); # Alois P. Heinz, Sep 25 2016
# third Maple program:
T:= proc(n, k) option remember; `if`(k<0 or k>2*n, 0,
`if`(n=0, 1, add(T(n-i, k-`if`(i>1, 1, 0))*
mul(n-j, j=1..i-1), i=1..n)))
end:
seq(seq(T(n,k), k=0..n/2), n=0..15); # Alois P. Heinz, Jul 16 2017
-
max = 12; egf = Exp[x*(1-y)]/(1-x)^y; s = Series[egf, {x, 0, max}, {y, 0, max}] // Normal; t[n_, k_] := SeriesCoefficient[s, {x, 0, n}, {y, 0, k}]*n!; t[0, 0] = t[1, 0] = 1; Table[t[n, k], {n, 0, max}, {k, 0, n/2}] // Flatten (* Jean-François Alcover, Jan 28 2014 *)
A137346
Coefficients of a special case of Poisson-Charlier polynomials. Triangle read by rows, T(n, k) for 0 <= k <= n.
Original entry on oeis.org
1, -2, 1, 4, -5, 1, -8, 20, -9, 1, 16, -78, 59, -14, 1, -32, 324, -360, 135, -20, 1, 64, -1520, 2254, -1165, 265, -27, 1, -128, 8336, -15232, 9954, -3045, 469, -35, 1, 256, -53872, 113868, -88508, 33649, -6888, 770, -44, 1, -512, 405600, -948840, 839684, -376278, 95025, -14028, 1194, -54
Offset: 0
{1},
{-2, 1},
{4, -5, 1},
{-8, 20, -9, 1},
{16, -78,59, -14, 1},
{-32, 324, -360, 135, -20, 1},
{64, -1520, 2254, -1165, 265, -27, 1},
{-128, 8336, -15232, 9954, -3045, 469, -35, 1},
{256, -53872, 113868, -88508, 33649, -6888, 770, -44, 1},
{-512, 405600, -948840, 839684, -376278, 95025, -14028, 1194, -54, 1},
{1024, -3492416, 8793216, -8592220,4373060, -1297569, 235473, -26370, 1770, -65, 1}
-
R := proc(n) add((-1)^k*binomial(n,k)* k!*2^(n-k)*binomial(-x, k), k=0..n);
expand(%) end: p := n -> seq((-1)^(n-k)*coeff(R(n), x, k), k=0..n):
seq(p(n), n = 0..9);
# Or:
egf := exp(-2*t)*(1+t)^x: ser := series(egf, t, 12): p := n -> coeff(ser, t, n):
seq(n!*seq(coeff(p(n), x, k), k=0..n), n=0..9); # Peter Luschny, Oct 27 2019
-
Ca[x, 0] = 1; Ca[x, 1] = -2 + x;
Ca[x_, n_] := Ca[x, n] = (x - n - 1) Ca[x, n - 1] - 2 (n - 1) Ca[x, n - 2];
Table[CoefficientList[Ca[x, n], x], {n, 0, 9}] // Flatten
(* The unsigned row polynomials (see Peter Bala's comment) are: *)
R[n_] := HypergeometricU[-n, 1 - n - x, 2];
Table[R[n], {n, 0, 6}] (* Peter Luschny, Oct 27 2019 *)
A124791
Row sums of number triangle A124790.
Original entry on oeis.org
1, 1, 1, 3, 5, 13, 29, 73, 181, 465, 1205, 3171, 8425, 22597, 61073, 166195, 454949, 1251985, 3461573, 9611191, 26787377, 74916661, 210178457, 591347989, 1668172841, 4717282753, 13369522249, 37970114703, 108045430901
Offset: 0
A172160
a(0)=1. a(n) = 2^(n-2)*(5-n), for n>0.
Original entry on oeis.org
1, 2, 3, 4, 4, 0, -16, -64, -192, -512, -1280, -3072, -7168, -16384, -36864, -81920, -180224, -393216, -851968, -1835008, -3932160, -8388608, -17825792, -37748736, -79691776, -167772160, -352321536, -738197504, -1543503872, -3221225472, -6710886400
Offset: 0
G.f. = 1 + 2*x + 3*x^2 + 4*x^3 + 4*x^4 - 16*x^6 - 64*x^7 + ... - _Michael Somos_, Apr 22 2022
-
Table[2^(n-2)*(5-n) -(1/4)*Boole[n==0], {n,0,40}] (* G. C. Greubel, Apr 21 2022 *)
-
[2^(n-2)*(5-n) -(1/4)*bool(n==0) for n in (1..40)] # G. C. Greubel, Apr 21 2022
Definition replaced with closed form by
R. J. Mathar, Feb 11 2010
A232774
Triangle T(n,k), read by rows, given by T(n,0)=1, T(n,1)=2^(n+1)-n-2, T(n,n)=(-1)^(n-1) for n > 0, T(n,k)=T(n-1,k)-T(n-1,k-1) for 1 < k < n.
Original entry on oeis.org
1, 1, 1, 1, 4, -1, 1, 11, -5, 1, 1, 26, -16, 6, -1, 1, 57, -42, 22, -7, 1, 1, 120, -99, 64, -29, 8, -1, 1, 247, -219, 163, -93, 37, -9, 1, 1, 502, -466, 382, -256, 130, -46, 10, -1, 1, 1013, -968, 848, -638, 386, -176, 56, -11, 1, 2036, -1981, 1816, -1486, 1024
Offset: 0
Triangle begins:
1;
1, 1;
1, 4, -1;
1, 11, -5, 1;
1, 26, -16, 6, -1;
1, 57, -42, 22, -7, 1;
1, 120, -99, 64, -29, 8, -1;
1, 247, -219, 163, -93, 37, -9, 1;
1, 502, -466, 382, -256, 130, -46, 10, -1;
1, 1013, -968, 848, -638, 386, -176, 56, -11, 1;
Showing 1-5 of 5 results.
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