A143395 -id:A143395 - cp's OEIS frontend

A225472 Triangle read by rows, k!*S_3(n, k) where S_m(n, k) are the Stirling-Frobenius subset numbers of order m; n >= 0, k >= 0.

1, 2, 3, 4, 21, 18, 8, 117, 270, 162, 16, 609, 2862, 4212, 1944, 32, 3093, 26550, 72090, 77760, 29160, 64, 15561, 230958, 1031940, 1953720, 1662120, 524880, 128, 77997, 1941030, 13429962, 39735360, 57561840, 40415760, 11022480, 256, 390369, 15996222, 165198852

Offset: 0

Peter Luschny, May 17 2013

The Stirling-Frobenius subset numbers are defined in A225468 (see also the Sage program).

			[n\k][0,     1,      2,       3,       4,       5,      6 ]
[0]   1,
[1]   2,     3,
[2]   4,    21,     18,
[3]   8,   117,    270,     162,
[4]  16,   609,   2862,    4212,    1944,
[5]  32,  3093,  26550,   72090,   77760,   29160,
[6]  64, 15561, 230958, 1031940, 1953720, 1662120, 524880.

Vincenzo Librandi, Rows n = 0..50, flattened
P. Bala, A 3 parameter family of generalized Stirling numbers.
Peter Luschny, Generalized Eulerian polynomials.
Peter Luschny, The Stirling-Frobenius numbers.

Cf. A131689 (m=1), A145901 (m=2), A225473 (m=4).

Cf. A225466, A225468, columns: A000079, 3*A016127, 3^2*2!*A016297, 3^3*3!*A025999.

SF_SO := proc(n, k, m) option remember;
if n = 0 and k = 0 then return(1) fi;
if k > n or k < 0 then return(0) fi;
m*k*SF_SO(n-1, k-1, m) + (m*(k+1)-1)*SF_SO(n-1, k, m) end:
seq(print(seq(SF_SO(n, k, 3), k=0..n)), n = 0..5);

EulerianNumber[n_, k_, m_] := EulerianNumber[n, k, m] = (If[ n == 0, Return[If[k == 0, 1, 0]]]; Return[(m*(n-k)+m-1)*EulerianNumber[n-1, k-1, m] + (m*k+1)*EulerianNumber[n-1, k, m]]); SFSO[n_, k_, m_] := Sum[ EulerianNumber[n, j, m]*Binomial[j, n-k], {j, 0, n}]; Table[ SFSO[n, k, 3], {n, 0, 8}, {k, 0, n}] // Flatten (* Jean-François Alcover, May 29 2013, translated from Sage *)

@CachedFunction
def EulerianNumber(n, k, m) :
    if n == 0: return 1 if k == 0 else 0
    return (m*(n-k)+m-1)*EulerianNumber(n-1, k-1, m)+ (m*k+1)*EulerianNumber(n-1, k, m)
def SF_SO(n, k, m):
    return add(EulerianNumber(n, j, m)*binomial(j, n - k) for j in (0..n))
for n in (0..6): [SF_SO(n, k, 3) for k in (0..n)]

For a recurrence see the Maple program.
T(n, 0) ~ A000079; T(n, 1) ~ A005057; T(n, n) ~ A032031.
From Wolfdieter Lang, Apr 10 2017: (Start)
E.g.f. for sequence of column k: exp(2*x)*(exp(3*x) - 1)^k, k >= 0. From the Sheffer triangle S2[3,2] = A225466 with column k multiplied with k!.
O.g.f. for sequence of column k is 3^k*k!*x^k/Product_{j=0..k} (1 - (2+3*j)*x), k >= 0.
T(n, k) = Sum_{j=0..k} (-1)^(k-j)*binomial(k, j)*(2+3*j)^n, 0 <= k <= n.
Three term recurrence (see the Maple program): T(n, k) = 0 if n < k , T(n, -1) = 0, T(0,0) = 1, T(n, k) = 3*k*T(n-1, k-1) + (2 + 3*k)*T(n-1, k) for n >= 1, k=0..n.
For the column scaled triangle (with diagonal 1s) see A225468, and the Bala link with (a,b,c) = (3,0,2), where Sheffer triangles are called exponential Riordan triangles.
(End)
The e.g.f. of the row polynomials R(n, x) = Sum_{k=0..n} T(n, k)*x^k is exp(2*z)/(1 - x*(exp(3*z) - 1)). - Wolfdieter Lang, Jul 12 2017

A154372 Triangle T(n,k) = (k+1)^(n-k)*binomial(n,k).

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 12, 9, 1, 1, 32, 54, 16, 1, 1, 80, 270, 160, 25, 1, 1, 192, 1215, 1280, 375, 36, 1, 1, 448, 5103, 8960, 4375, 756, 49, 1, 1, 1024, 20412, 57344, 43750, 12096, 1372, 64, 1

Offset: 0

Paul Curtz, Jan 08 2009

From A152650/A152656,coefficients of other exponential polynomials(*). a(n) is triangle A152818 where terms of each column is divided by the beginning one. See A000004, A001787(n+1), A006043=2*A027472, A006044=6*A038846.
(*) Not factorial as written in A006044. See A000110, Bell-Touchard. Second diagonal is 1,4,9,16,25, denominators of Lyman's spectrum of hydrogen, A000290(n+1) which has homogeneous indices for denominators series of Rydberg-Ritz spectrum of hydrogen.
The matrix inverse starts
      1;
     -1,      1;
      3,     -4,     1;
    -16,     24,    -9,     1;
    125,   -200,    90,   -16,   1;
  -1296,   2160, -1080,   240, -25,   1;
  16807, -28812, 15435, -3920, 525, -36, 1;
.. compare with A122525 (row reversed). - R. J. Mathar, Mar 22 2013
From Peter Bala, Jan 14 2015: (Start)
Exponential Riordan array [exp(z), z*exp(z)]. This triangle is the particular case a = 0, b = 1, c = 1 of the triangle of generalized Stirling numbers of the second kind S(a,b,c) defined in the Bala link. Cf. A059297.
This is the triangle of connection constants when expressing the monomials x^n as a linear combination of the basis polynomials (x - 1)*(x - k - 1)^(k-1), k = 0,1,2,.... For example, from row 3 we have x^3 = 1 + 12*(x - 1) + 9*(x - 1)*(x - 3) + (x - 1)*(x - 4)^2.
Let M be the infinite lower unit triangular array with (n,k)-th entry (k*(n - k + 1) + 1)/(k + 1)*binomial(n,k). M is the row reverse of A145033. For k = 0,1,2,... define M(k) to be the lower unit triangular block array
/I_k 0\
\ 0  M/ having the k X k identity matrix I_k as the upper left block; in particular, M(0) = M. The infinite product M(0)*M(1)*M(2)*..., which is clearly well-defined, is equal to the present triangle. See the Example section. (End)
T(n,k) is also the number of idempotent partial transformations of {1,2,...,n} having exactly k fixed points. - Geoffrey Critzer, Nov 25 2021

			With the array M(k) as defined in the Comments section, the infinite product M(0)*M(1)*M(2)*... begins
/1      \ /1        \ /1        \      /1        \
|1 1     ||0 1       ||0 1      |      |1  1      |
|1 3 1   ||0 1 1     ||0 0 1    |... = |1  4  1   |
|1 6 5 1 ||0 1 3 1   ||0 0 1 1  |      |1 12  9  1|
|...     ||0 1 6 5 1 ||0 0 1 3 1|      |...       |
|...     ||...       ||...      |      |          |
- _Peter Bala_, Jan 13 2015

G. C. Greubel, Table of n, a(n) for n = 0..1274
Peter Bala, A 3 parameter family of generalized Stirling numbers
Emanuele Munarini, Combinatorial identities involving the central coefficients of a Sheffer matrix, Applicable Analysis and Discrete Mathematics (2019) Vol. 13, 495-517.

Cf. A080108, A152818, A059297, A145033.

/* As triangle */ [[(k+1)^(n-k)*Binomial(n,k) : k in [0..n]]: n in [0.. 15]]; // Vincenzo Librandi, Sep 15 2016

T[n_, k_] := (k + 1)^(n - k)*Binomial[n, k]; Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* G. C. Greubel, Sep 15 2016 *)

T(n,k) = (k+1)^(n-k)*binomial(n,k). k!*T(n,k) gives the entries for A152818 read as a triangular array.
E.g.f.: exp(x*(1+t*exp(x))) = 1 + (1+t)*x + (1+4*t+t^2)*x^2/2! + (1+12*t+9*t^2+t*3)*x^3/3! + .... O.g.f.: Sum_{k>=1} (t*x)^(k-1)/(1-k*x)^k = 1 + (1+t)*x + (1+4*t+t^2)*x^2 + .... Row sums are A080108. - Peter Bala, Oct 09 2011
From Peter Bala, Jan 14 2015: (Start)
Recurrence equation: T(n+1,k+1) = T(n,k+1) + Sum_{j = 0..n-k} (j + 1)*binomial(n,j)*T(n-j,k) with T(n,0) = 1 for all n.
Equals the matrix product A007318 * A059297. (End)

A290319 Triangle read by rows: T(n, k) is the Sheffer triangle ((1 - 4x)^(-1/4), (-1/4)log(1 - 4*x)). A generalized Stirling1 triangle.

Original entry on oeis.org

1, 1, 1, 5, 6, 1, 45, 59, 15, 1, 585, 812, 254, 28, 1, 9945, 14389, 5130, 730, 45, 1, 208845, 312114, 122119, 20460, 1675, 66, 1, 5221125, 8011695, 3365089, 633619, 62335, 3325, 91, 1, 151412625, 237560280, 105599276, 21740040, 2441334, 158760, 5964, 120, 1, 4996616625, 7990901865, 3722336388, 823020596, 102304062, 7680414, 355572, 9924, 153, 1, 184874815125, 300659985630, 145717348221, 34174098440, 4608270890, 386479380, 20836578, 722760, 15585, 190, 1

Offset: 0

Wolfdieter Lang, Aug 08 2017

This generalization of the unsigned Stirling1 triangle A132393 is called here |S1hat[4,1]|.
The signed matrix S1hat[4,1] with elements (-1)^(n-k)*|S1hat[4,1]|(n, k) is the inverse of the generalized Stirling2 Sheffer matrix S2hat[4,1] with elements S2[4,1](n, k)/d^k, where S2[4,1] is Sheffer (exp(x), exp(4*x) - 1), given in A285061. See also the P. Bala link below for the scaled and signed version s_{(4,0,1)}.
For the general |S1hat[d,a]| case see a comment in A286718.

			The triangle T(n, k) begins:
  n\k         0         1         2        3       4      5    6   7  8 ...
  0:          1
  1:          1         1
  2:          5         6         1
  3:         45        59        15        1
  4:        585       812       254       28       1
  5:       9945     14389      5130      730      45      1
  6:     208845    312114    122119    20460    1675     66    1
  7:    5221125   8011695   3365089   633619   62335   3325   91   1
  8:  151412625 237560280 105599276 21740040 2441334 158760 5964 120  1
  ...
From _Wolfdieter Lang_, Aug 11 2017: (Start)
Recurrence: T(4, 2) = T(3, 1) + (16 - 3)*T(3, 2) = 59 + 13*15 = 254.
Boas-Buck recurrence for column k=2 and n=4:
T(4, 2) = (4!/2)*(4*(1 + 8*(5/12))*T(2, 2)/2! + 1*(1 + 8*(1/2))*T(3,2)/3!) = (4!/2)*(2*13/3 + 5*15/3!) = 254. (End)

Paolo Xausa, Table of n, a(n) for n = 0..11475 (rows 0..150 of triangle, flattened).
Peter Bala, A 3 parameter family of generalized Stirling numbers.
Wolfdieter Lang, On Sums of Powers of Arithmetic Progressions, and Generalized Stirling, Eulerian and Bernoulli Numbers, arXiv:math/1707.04451 [math.NT], July 2017.

S2[d,a] for [d,a] = [1,0], [2,1], [3,1], [3,2], [4,1] and [4,3] is A048993, A154537, A282629, A225466, A285061 and A225467, respectively.
|S1hat[d,a]| for [d,a] = [1,0], [2,1], [3,1], [3,2] and [4,3] is A132393, A028338, A286718, A225470 and A225471, respectively.
Columns k=0..3 give A007696, A024382(n-1), A383700, A383701.
Row sums: A001813. Alternating row sums: A000007.

FoldList[Join[Table[If[i == 1, 0, #[[i-1]]] + (4*#2 - 3)*#[[i]], {i, Length[#]}], {1}] &, {1}, Range[10]] (* Paolo Xausa, Aug 18 2025 *)

Recurrence: T(n, k) = T(n-1, k-1) + (4*n - 3)*T(n-1, k), for n >= 1, k = 0..n, and T(n, -1) = 0, T(0, 0) = 1 and T(n, k) = 0 for n < k.
E.g.f. of row polynomials R(n, x) = Sum_{k=0..n} T(n, k)*x^k (i.e., e.g.f. of the triangle): (1 - 4*z)^{-(x + 1)/4}.
E.g.f. of column k is (1 - 4*x)^(-1/4)*((-1/4)*log(1 - 4*x))^k/k!.
Recurrence for row polynomials is R(n, x) = (x+1)*R(n-1, x+4), with R(0, x) = 1. Row polynomial R(n, x) = risefac(4,1;x,n) with the rising factorial risefac(d,a;x,n) :=Product_{j=0..n-1} (x + (a + j*d)). (For the signed case see the Bala link, eq. (16)).
T(n, k) = sigma^{(n)}{n-k}(a_0, a_1, ..., a{n-1}) with the elementary symmetric functions with indeterminates a_j = 1 + 4*j.
T(n, k) = Sum_{j=0..n-k} binomial(n-j, k)*|S1|(n, n-j)*4^j, with the unsigned Stirling1 triangle |S1| = A132393.
Boas-Buck type recurrence for column sequence k: T(n, k) = (n!/(n - k)) * Sum_{p=k..n-1} 4^(n-1-p)*(1 + 4*k*beta(n-1-p))*T(p, k)/p!, for n > k >= 0, with input T(k, k) = 1, and beta(k) = A002208(k+1)/A002209(k+1), beginning with {1/2, 5/12, 3/8, 251/720, ...}. See a comment and references in A286718. - Wolfdieter Lang, Aug 11 2017

A143399 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=4.

Original entry on oeis.org

0, 0, 0, 0, 1, 30, 545, 7770, 95781, 1071630, 11192665, 111095490, 1060634861, 9822843030, 88799732385, 787259974410, 6869327386741, 59158464019230, 503954741177705, 4254156112792530, 35637875826743421, 296621138907400230, 2455329298857576625

Offset: 0

Alois P. Heinz, Aug 12 2008

nonn

a(n) is also the number of forests of 4 labeled rooted trees of height at most 1 with n labels, where any root may contain >= 1 labels.

This gives also the fifth column of the Sheffer triangle A143496 (4-restricted Stirling2 numbers). See the e.g.f. given below. See also A193685 for Sheffer comments and the hint for the proof in the o.g.f. formula there. - Wolfdieter Lang, Oct 08 2011

Alois P. Heinz, Table of n, a(n) for n = 0..350
Index entries for sequences related to rooted trees
Index entries for linear recurrences with constant coefficients, signature (30, -355, 2070, -5944, 6720).

4th column of A143395.

a:= proc(k::nonnegint) local M; M := Matrix(k+1, (i,j)-> if (i=j-1) then 1 elif j=1 then [seq(-1* coeff(product(1-t*x, t=k..2*k), x, u), u=1..k+1)][i] else 0 fi); p-> (M^p)[1, k+1] end(4): seq(a(n), n=0..30);

LinearRecurrence[{30,-355,2070,-5944,6720},{0,0,0,0,1},30] (* Harvey P. Dale, Mar 12 2013 *)

G.f.: x^4/((1-4x)(1-5x)(1-6x)(1-7x)(1-8x)).
a(n) = 30a(n-1) -355a(n-2) +2070a(n-3) -5944a(n-4) +6720a(n-5).
E.g.f.: exp(4*x)*((exp(x)-1)^4)/4!. - Wolfdieter Lang, Oct 08 2011

A143400 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=5.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 45, 1190, 24150, 416451, 6427575, 91549480, 1227283200, 15695180501, 193333245105, 2310273772170, 26927270656650, 307413790470151, 3449088814306635, 38132767214613260, 416342920938136500, 4497187699884973401, 48129773048982636165

Offset: 0

Alois P. Heinz, Aug 12 2008

nonn

a(n) is also the number of forests of 5 labeled rooted trees of height at most 1 with n labels, where any root may contain >= 1 labels.

Alois P. Heinz, Table of n, a(n) for n = 0..300
Index entries for sequences related to rooted trees
Index entries for linear recurrences with constant coefficients, signature (45, -835, 8175, -44524, 127860, -151200).

5th column of A143395.

a := proc(k::nonnegint) local M; M := Matrix(k+1, (i,j)-> if (i=j-1) then 1 elif j=1 then [seq(-1* coeff(product(1-t*x, t=k..2*k), x,u), u=1..k+1)][i] else 0 fi); p-> (M^p)[1,k+1] end(5); seq(a(n), n=0..30);

CoefficientList[Series[x^5/((1-5x)(1-6x)(1-7x)(1-8x)(1-9x)(1-10x)),{x,0,30}],x] (* or *) LinearRecurrence[{45,-835,8175,-44524,127860,-151200},{0,0,0,0,0,1},30] (* Harvey P. Dale, Aug 30 2018 *)

G.f.: x^5/((1-5x)(1-6x)(1-7x)(1-8x)(1-9x)(1-10x)).

E.g.f.: exp(5*x)*((exp(x)-1)^5)/5!.

A143401 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=6.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 63, 2282, 62370, 1428987, 28979181, 537306484, 9302333040, 152587968533, 2396472657579, 36320866824606, 534421447961310, 7670116319449039, 107781064078390857, 1487396442778796648, 20208696810429799980, 270879169288278532905

Offset: 0

Alois P. Heinz, Aug 12 2008

nonn

a(n) is also the number of forests of 6 labeled rooted trees of height at most 1 with n labels, where any root may contain >= 1 labels.

Alois P. Heinz, Table of n, a(n) for n = 0..300
Index entries for sequences related to rooted trees

6th column of A143395.

a:= proc(k::nonnegint) local M; M:= Matrix(k+1, (i,j)-> if (i=j-1) then 1 elif j=1 then [seq(-1* coeff(product(1-t*x, t=k..2*k), x,u), u=1..k+1)][i] else 0 fi); p-> (M^p)[1,k+1] end(6); seq(a(n), n=0..27);

G.f.: x^6/((1-6x)(1-7x)(1-8x)(1-9x)(1-10x)(1-11x)(1-12x)).

E.g.f.: exp(6*x)*((exp(x)-1)^6)/6!.

A143402 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=7.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 84, 3990, 141120, 4138827, 106469748, 2484848080, 53791898160, 1096912870053, 21307466872692, 397605494092170, 7173885616672320, 125794299357058879, 2152559266567924116, 36065247772657686660, 593280221500152370800

Offset: 0

Alois P. Heinz, Aug 12 2008

nonn

a(n) is also the number of forests of 7 labeled rooted trees of height at most 1, with n labels, where any root may contain >= 1 labels.

Alois P. Heinz, Table of n, a(n) for n = 0..300
Index entries for sequences related to rooted trees

7th column of A143395.

a:= proc(k::nonnegint) local M; M:= Matrix(k+1, (i,j)-> if (i=j-1) then 1 elif j=1 then [seq(-1* coeff(product(1-t*x, t=k..2*k), x,u), u=1..k+1)][i] else 0 fi); p-> (M^p)[1,k+1] end(7): seq(a(n), n=0..30);

G.f.: x^7/((1-7x)(1-8x)(1-9x)(1-10x)(1-11x)(1-12x)(1-13x)(1-14x)).

E.g.f.: exp(7*x)*((exp(x)-1)^7)/7!.

A143403 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=8.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 108, 6510, 289080, 10550067, 335170836, 9597839680, 253489991040, 6275077781973, 147318890173884, 3309320153700210, 71623038281001480, 1501654449863348119, 30633757929391948452, 610246760750629071300, 11906371167306982146000

Offset: 0

Alois P. Heinz, Aug 12 2008

nonn

a(n) is also the number of forests of 8 labeled rooted trees of height at most 1 with n labels, where any root may contain >= 1 labels.

Alois P. Heinz, Table of n, a(n) for n = 0..250
Index entries for sequences related to rooted trees

8th column of A143395.

a:= proc(k::nonnegint) local M; M:= Matrix(k+1, (i,j)-> if (i=j-1) then 1 elif j=1 then [seq(-1* coeff(product(1-t*x, t=k..2*k), x,u), u=1..k+1)][i] else 0 fi); p-> (M^p)[1,k+1] end(8); seq(a(n), n=0..27);

G.f.: x^8/((1-8x)(1-9x)(1-10x)(1-11x)(1-12x)(1-13x)(1-14x)(1-15x)(1-16x)).

E.g.f.: exp(8*x)*((exp(x)-1)^8)/8!.

A143404 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=9.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 135, 10065, 547965, 24336312, 934863930, 32189799070, 1017281878470, 30001945084683, 835898091070185, 22206607023852615, 566594907018764715, 13964270139973201114, 333991935681805199700, 7781827783346875932300

Offset: 0

Alois P. Heinz, Aug 12 2008

nonn

a(n) is also the number of forests of 9 labeled rooted trees of height at most 1 with n labels, where any root may contain >= 1 labels.

Alois P. Heinz, Table of n, a(n) for n = 0..300
Index entries for sequences related to rooted trees
Index entries for linear recurrences with constant coefficients, signature (135, -8160, 290790, -6765213, 107358615, -1176812090, 8797620060, -42924478536, 123418922400, -158789030400).

9th column of A143395.

a:= proc(k::nonnegint) local M; M:= Matrix(k+1, (i,j)-> if (i=j-1) then 1 elif j=1 then [seq(-1* coeff(product(1-t*x, t=k..2*k), x,u), u=1..k+1)][i] else 0 fi); p-> (M^p)[1,k+1] end(9): seq(a(n), n=0..30);

CoefficientList[Series[x^9/Product[1-t x,{t,9,18}],{x,0,30}],x] (* or *) LinearRecurrence[{135,-8160,290790,-6765213,107358615,-1176812090, 8797620060,-42924478536,123418922400, -158789030400}, {0,0,0,0,0,0,0,0,0,1},31] (* Harvey P. Dale, May 22 2012 *)

G.f.: x^9/ ((1-9x)(1-10x)(1-11x)(1-12x)(1-13x)(1-14x)(1-15x)(1-16x)(1-17x)(1-18*x)).
a(n)=0 for n<9, a(9)=1, a(n) = 135*a(n-1) -8160*a(n-2) +290790*a(n-3) -6765213*a(n-4) +107358615*a(n-5) -1176812090*a(n-6) +8797620060*a(n-7) -42924478536*a(n-8) +123418922400*a(n-9) -158789030400*a(n-10). - Harvey P. Dale, May 22 2012
E.g.f.: exp(9*x)*((exp(x)-1)^9)/9!. - Alois P. Heinz, May 04 2016

A383869 a(n) = [x^n] 1/Product_{k=0..n} (1 - (n+k)*x).

Original entry on oeis.org

1, 3, 55, 1890, 95781, 6427575, 537306484, 53791898160, 6275077781973, 835898091070185, 125195263380478655, 20825548503275385870, 3809430011164368694260, 759987002381075483922180, 164221938436980055710082200, 38209754165858724861944820000, 9524153723280871205135022364485

Offset: 0

Seiichi Manyama, May 13 2025

nonn

Central terms of triangle A143395.

Cf. A007820, A129506.

Table[SeriesCoefficient[1/Product[(1 - (n + k)*x), {k, 0, n}], {x, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, May 17 2025 *)

a(n) = sum(k=0, n, (-1)^(n-k)*(n+k)^(2*n)*binomial(n, k))/n!;

a(n) = (1/n!) * Sum_{k=0..n} (-1)^(n-k) * (n+k)^(2*n) * binomial(n,k).
a(n) = Sum_{k=0..n} n^(n-k) * binomial(2*n,n+k) * Stirling2(n+k,n).
a(n) = Sum_{k=0..n} (-1)^k * (2*n)^(n-k) * binomial(2*n,n+k) * Stirling2(n+k,n).
a(n) ~ (r-1)^((r-1)*n) * (1+r)^(2*n + 1) * exp(n) * n^(n - 1/2) / (sqrt(2*Pi*(1 + (4-r)*r)) * r^(r*n)), where r = 2.106565648173949260853515992430777519716829316322... is the root of the equation exp(2/(1+r)) = r/(r-1). - Vaclav Kotesovec, May 17 2025

cp's OEIS Frontend

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A154372 Triangle T(n,k) = (k+1)^(n-k)*binomial(n,k).

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A290319 Triangle read by rows: T(n, k) is the Sheffer triangle ((1 - 4*x)^(-1/4), (-1/4)*log(1 - 4*x)). A generalized Stirling1 triangle.

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A143399 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=4.

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A143400 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=5.

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A143401 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=6.

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A143402 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=7.

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A143403 Expansion of x^k/Product_{t=k..2k} (1-tx) for k=8.

A290319 Triangle read by rows: T(n, k) is the Sheffer triangle ((1 - 4x)^(-1/4), (-1/4)log(1 - 4*x)). A generalized Stirling1 triangle.