A036039 -id:A036039 - cp's OEIS frontend

A145370 Lower triangular array, called S1hat(-4), related to partition number array A145369.

1, 4, 1, 12, 4, 1, 24, 28, 4, 1, 24, 72, 28, 4, 1, 0, 264, 136, 28, 4, 1, 0, 384, 456, 136, 28, 4, 1, 0, 864, 1344, 712, 136, 28, 4, 1, 0, 576, 4128, 2112, 712, 136, 28, 4, 1, 0, 576, 7488, 7968, 3136, 712, 136, 28, 4, 1, 0, 0, 13248, 20544, 11040, 3136, 712, 136, 28, 4, 1, 0, 0

Offset: 1

Wolfdieter Lang, Oct 17 2008

If in the partition array M31hat(-4):=A145369 entries belonging to partitions with the same parts number m are summed one obtains this triangle of numbers S1hat(-4). In the same way the signless Stirling1 triangle |A008275| is obtained from the partition array M_2 = A036039.

The first column is [1,4,12,24,24,0,0,0,...]= A008279(4,n-1), n>=1.

			Triangle begins:
  [1];
  [4,1];
  [12,4,1];
  [24,28,4,1];
  [24,72,28,4,1];
  ...

Wolfdieter Lang, First 10 rows of the array and more.
Wolfdieter Lang, Combinatorial Interpretation of Generalized Stirling Numbers, J. Int. Seqs. Vol. 12 (2009) 09.3.3.

Cf. A145371 (row sums).

a(n,m) = sum(product(S1(-4;j,1)^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n, Y and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S1(-4,n,1)= A008279(4,n-1) = [1,4,12,24,24,0,0,0,...], n>=1.

A231846 Polynomials for total Pontryagin classes. Refinement of double Pochhammer triangle.

Original entry on oeis.org

1, 1, 2, 1, 8, 6, 1, 48, 32, 12, 12, 1, 384, 240, 160, 80, 60, 20, 1, 3840, 2304, 1440, 640, 720, 960, 120, 160, 180, 30, 1, 46080, 26880, 16128, 13440, 8064, 10080, 4480, 3360, 1680, 3360, 840, 280, 420, 42, 1, 645120, 368640, 215040, 172032, 80640, 107520, 129024, 107520, 40320, 35840, 21504, 40320, 17920, 26880, 1680, 3360, 8960, 3360, 448, 840, 56, 1

Offset: 0

Tom Copeland, Nov 14 2013

The W. Lang link in A036039 explicitly gives the first several cycle index polynomials for the symmetric group S_n, or the partition polynomials for the refined Stirling numbers of the first kind. In line with the discussion in the Fecko link, null the indeterminates with odd indices, divide the 2n-th partition polynomial by the double factorial of odd numbers given in A001147, and re-index. The sum of the resulting row coefficients are also equal to A001147.

			In terms of the trace of a curvature form Tr(F^n)={n} or indeterminates c_n=[n]:
P_0 = 1,
P_1 = Tr(F^2) = {2}
    = c_1 = [1],
P_2 = 2Tr(F^4)+Tr(F^2)^2 = 2{4}+{2}^2
    = 2c_2+ (c_1)^2 = 2[2]+[1]^2,
P_3 = 8Tr(F^6)+6Tr(F^2)Tr(F^4)+Tr(F^2)^3= 8{6}+6{2}{4}+{2}^3
    = 8c_3+6c_1 c_2+(c_1)^3 = 8[3]+6[1][2]+[1]^3,
P_4 = 48{8}+32{2}{6}+12{4}^2+12{2}^2{4}+{2}^4
    = 48[4]+32[1][3]+12[2]^2+12[1]^2[2]+[1]^4,
P_5 = 384{10}+240{2}{8}+160{4}{6}+80{2}^2{6}
      + 60{2}{4}^2+20{2}^3{4}+{2}^5
    = 384[5]+240[1][4]+160[2][3]+80[1]^2[3]
      + 60[1][2]^2+20[1]^3[2]+[1]^5
P_6 = 3840[6]+2304[1][5]+1440[2][4]+640[3]^2+720[1]^2[4]
  +960[1][2][3]+120[2]^3+160[1]^3[3]+180[1]^2[2]^2+30[1]^4[2]+[1]^6
P_7 = 46080[7]+26880[1][6]+16128[2][5]+13440[3][4]+8064[1]^2[5]
  +10080[1][2][4]+4480[1][3]^2+3360[2]^2[3]+1680[1]^3[4]
  +3360[1]^2[2][3]+840[1][2]^3+280[1]^4[3]+420[1]^3[2]^2+42[1]^5[2]+[1]^7
....
Summing over partitions with the same number of blocks gives the unsigned double Pochhammer triangle A039683. Row sums are A001147. Multiplying P_n by the row sum gives the 2n-th partition polynomial of A036039 with its odd-indexed indeterminates nulled.
For c_1 = c_2 = x and c_n = 0 otherwise, see A119275. Let Omega(t) = xi(1/2 + i*t)/xi(1/2) where xi is the Landau version of the Riemann xi function, t is real, and i^2 = -1. The Taylor series coefficients vanish for odd order derivatives and, for even, are c_(2n) = Omega^(2n)(0) = (-1)^n * xi^(2n)(1/2) / xi(1/2) = A001147(n) * P_n as in the Example section with F^(2n) = -2 * Sum(1/x_k^(2n)) = -2 * Tr_(2n) where x_k is the imaginary part of the k-th zero of the Riemann zeta function and k ranges over all the zeros above the real axis. E.g., (see the Mathematics Stack Exchange question) summing over the first several thousands of zeros, c_4 = A001147(2)*P_2 = 3*[2*(-2*Tr_4) + (-2*Tr_2)^2] = 12*[-(0.000372) + (0.02311)^2] = .005962 and c_4 = xi^(4)*(1/2)/xi(1/2) = 0.002963/0.497 = 0.005962 (rounding off). Conversely, the Tr_(2n) can be calculated from the c_n using the Faber polynomials (A263916), as indicated in A036039. See Coffey for Taylor coefficients of Omega(t) about t = 0 and the MSE question for Tr_(2n). The traces are convergent and any zeros in the critical strip off the critical line would have a slightly more complicated real contribution to the traces but negligible to any practical order. - _Tom Copeland_, May 27 2020

M. Coffey, Relations and positivity results for derivatives of the Riemann xi function, J. Comput. Appl. Math. 166(2) (2004), 525-534.
Tom Copeland, Appells and Roses: Newton, Leibniz, Euler, Riemann and Symmetric Polynomials, 2020.
M. Fecko, Selected topological concepts used in physics pp. 37-41 and 56-58.
Mathematics Stack Exchange, Sums of the reciprocals of powers of the imaginary part of the nontrivial Riemann zeros, a MSE question posed by T. Copeland and answered by G. Helms, 2020.
Wikipedia, Pontryagin class
Y. Zhang, A brief introduction to characteristic classes from the differentiable viewpoint p. 27.

Cf. A000165, A001147, A036039, A055140, A119275.
Cf. A263916.
The terms are indexed by partitions in the Abramowitz and Stegun order, A036036.

rows[n_] := {{1}}~Join~With[{s = Exp[Sum[b[k] t^k/(2 k), {k, n}] + O[t]^(n+1)]}, Table[Expand@Coefficient[(2 k)!! s, t^k Product[b[t], {t, p}]], {k, n}, {p, Sort[Sort /@ IntegerPartitions[k]]}]];
rows[8] // Flatten (* Andrey Zabolotskiy, Feb 19 2024 *)

From Tom Copeland, Oct 11 2016: (Start)
A generating function for the polynomials PB_n[b_2,b_4,..,b_(2n)] of this array is
exp[b_2 y^2/2 + b_4 y^4/4 + b_6 y^6/6 + ...] = Sum_{n >= 0} PB_n y^(2n) / A000165(n) = Sum_{n >= 0} St1[2n,0,b_2,0,b_4,0,..,b_(2n)] y^(2n) / (2n)! = Sum_{n >= 0} PB_n *(y/sqrt(2))^(2n) / n! with b_n = Tr(F^n), as in the examples, and St1(n,b_1,b_2,..,b_n), the partition polynomials of A036039. Then St1[2n,0,b_2,0,b_4,..,0,b_(2n)] = A001147(n) * PB_n.
The polynomials PC_n(c_1,c_2,..,c_n) of this array with c_k = b_(2k) are an Appell sequence in the indeterminate c_1 with lowering operator L = d/d(c_1), i.e., L*PC_n(c_1,..,c_n) = d(PC_n)/d(c_1) = n * PC_(n-1)[c_1,..,c_(n-1)].
With [PC.(c_1,c_2,..)]^n = PC_n(c_1,..,c_n), the e.g.f. is G(t,c_1,c_2,..) = exp[t*PC.(0,c_2,c_3,..)] * exp(t*c_1) = exp{t*[c_1 + PC.(0,c_2,c_3,..)]} = exp[t*PC.(c_1,c_2,..)] = exp[(1/2) * sum_{n > 0} c_n (2t)^n/n ] = exp[-log(1-2c.t) / 2], where, umbrally, (c.)^n = c_n.
The raising operator is R = d[log(G(L,c_1,c_2,..))]/dL = sum_{n >= 0} 2^n * c_(n+1) * (d/dc_1)^n = c./(1-2c.L), umbrally. R PC_n(c_1,..,c_n) = P_(n+1)[c_1,..,c_(n+1)].
Another generator: G(L,0,c_2,c_3,..) (c_1)^n = PC_n(c_1,c_2,..,c_n).
The Appell umbral compositional inverse sequence UPC_n to the PC_n sequence has e.g.f. UG(t,c_1,c_2,..) = [1 / G(t,0,c_2,c_3,..)] *  exp(t*c_1) with lowering operator L, as above, and raising operator RU = c_1 - sum_{n > 0} 2^n * c_(n+1) * (d/dc_1)^n. It follows that UPC_n(c_1,c_2,..,c_n) = PC_n(c_1,-c_2,..,-c_n) and PC_n(PC.(c_1,c_2,..),-c_2,-c_3,..) = PC_n(PC.(c_1,-c_2,-c_3,..),c_2,c_3,..) = (c_1)^n, e.g., PC_2(PC.(c_1,-c_2,..),c_2) = 2 c_2 + (PC.(c_1,-c_2,..))^2 = 2 c_2 + PC_2(c_1,-c_2) = 2 c_2 + 2 (-c_2) + (c_1)^2 = (c_1)^2.
Letting c_1 = x and all other c_n = 1 gives the row polynomials of A055140.
(End)

Polynomials P_6 and P_7 added by Tom Copeland, Oct 11 2016
Correction to P_3 in Example by Tom Copeland, May 27 2020
Terms in rows 6-7 reordered, row 8 added by Andrey Zabolotskiy, Feb 19 2024

A124773 Number of permutations associated with compositions in standard order.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 1, 6, 6, 3, 3, 2, 2, 1, 1, 24, 24, 12, 12, 8, 8, 4, 4, 6, 6, 3, 3, 2, 2, 1, 1, 120, 120, 60, 60, 40, 40, 20, 20, 30, 30, 15, 15, 10, 10, 5, 5, 24, 24, 12, 12, 8, 8, 4, 4, 6, 6, 3, 3, 2, 2, 1, 1, 720, 720, 360, 360, 240, 240, 120, 120, 180, 180, 90, 90, 60, 60, 30

Offset: 0

Franklin T. Adams-Watters, Nov 06 2006

The standard order of compositions is given by A066099.

Arrange the cycles of the permutation by the smallest member of each cycle and read off the cycle sizes. E.g., for (1)(24)(3), the associated composition is 1,2,1.

			Composition number 11 is 2,1,1; the associated permutations are (12)(3)(4), (13)(2)(4) and (14)(2)(3), so a(11) = 3.
The table starts:
1
1
1 1
2 2 1 1

Cf. A066099, A124772, A124774, A011782 (row lengths), A000142 (row sums), A036039.

For composition b(1),...,b(k), a(n) = Product_{i=1}^n C((Sum_{j=i}^n b(j)) - 1, b(i)-1) * (b(i)-1)!.

A124774 Multinomial coefficients for compositions in standard order.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 3, 6, 1, 4, 6, 12, 4, 12, 12, 24, 1, 5, 10, 20, 10, 30, 30, 60, 5, 20, 30, 60, 20, 60, 60, 120, 1, 6, 15, 30, 20, 60, 60, 120, 15, 60, 90, 180, 60, 180, 180, 360, 6, 30, 60, 120, 60, 180, 180, 360, 30, 120, 180, 360, 120, 360, 360, 720, 1, 7, 21, 42, 35, 105

Offset: 0

Franklin T. Adams-Watters, Nov 06 2006

The standard order of compositions is given by A066099.

Number of ways to distribute labeled objects into boxes, with the number of objects in each box being specified by the composition.

			Composition number 11 is 2,1,1; there are 6 choices for the pair of objects in the first box, then 2 choices for the object in the next box, so a(11) = 6*2 = 12.
The table starts:
1
1
1 2
1 3 3 6

Alois P. Heinz, Rows n = 0..14, flattened
Thomas Garrity and Jacob Lehmann Duke, Ergodicity and Algebraticity of the Fast and Slow Triangle Maps, arXiv:2409.05822 [math.DS], 2024. See p. 22.

Cf. A066099, A124773, A011782 (row lengths), A000670 (row sums), A036039.

For composition b(1),...,b(k), a(n) = (Sum_{i=1}^k b(i))! / (Product_{i=1}^k b(i)!).

A145373 Lower triangular array, called S1hat(-5), related to partition number array A145372.

Original entry on oeis.org

1, 5, 1, 20, 5, 1, 60, 45, 5, 1, 120, 160, 45, 5, 1, 120, 820, 285, 45, 5, 1, 0, 1920, 1320, 285, 45, 5, 1, 0, 6600, 5420, 1945, 285, 45, 5, 1, 0, 9600, 23600, 7920, 1945, 285, 45, 5, 1, 0, 21600, 66600, 41100, 11045, 1945, 285, 45, 5, 1, 0, 14400, 189600, 151600, 53600, 11045

Offset: 1

Wolfdieter Lang, Oct 17 2008

If in the partition array M31hat(-5):=A145372 entries belonging to partitions with the same parts number m are summed one obtains this triangle of numbers S1hat(-5). In the same way the signless Stirling1 triangle |A008275| is obtained from the partition array M_2 = A036039.

The first column is [1,5,20,60,120,120,0,0,0,...]= A008279(5,n-1), n>=1.

			Triangle begins:
  [1];
  [5,1];
  [20,5,1];
  [60,45,5,1];
  [120,160,45,5,1];
  ...

Wolfdieter Lang, First 10 rows of the array and more.
Wolfdieter Lang, Combinatorial Interpretation of Generalized Stirling Numbers, J. Int. Seqs. Vol. 12 (2009) 09.3.3.

Cf. A145374 (row sums).

a(n,m) = sum(product(S1(-5;j,1)^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. S1(-5,n,1)= A008279(5,n-1) = [1,5,20,60,120,120,0,0,0,...], n>=1.

A164341 Irregular triangle read by rows: a(n,m) counts the decompositions into involutions of a permutation that has a cycle structure given by the m-th partition of n.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 4, 3, 6, 4, 10, 5, 4, 6, 6, 6, 8, 26, 6, 5, 8, 12, 8, 6, 20, 12, 12, 20, 76, 7, 6, 10, 12, 10, 8, 12, 18, 16, 12, 20, 30, 24, 52, 232, 8, 7, 12, 15, 20, 12, 10, 12, 24, 24, 20, 16, 24, 18, 76, 40, 24, 40, 78, 60, 152, 764, 9, 8, 14, 18, 20, 14, 12, 15, 20, 30, 24, 54

Offset: 1

Wouter Meeussen, Aug 13 2009

Partitions are in Abramowitz and Stegun ordering. First column is n. The n-th row has A000041(n) columns.

If a(n,m) is multiplied by weighing factor A036039(n,m) (Triangle of multinomial coefficients "M_2") then the resulting rows add to A000085(n)^2 (square of count of involutions).

			Table begins 1; 2,2; 3,2,4; 4,3,6,4,10; 5,4,6,6,6,8,26; a(7,7)= 12 since the partition 3;3;1 represents a cycle structure of a permutation that can be decomposed into involutions in 12 ways: 3*3=9 ways by splitting each 3-cycle into a 1-cycle and a 2-cycle, and 3 more ways by combining both 3-cycles to produce three 2-cycles.

T. Kyle Petersen and Bridget Eileen Tenner, How to write a permutation as a product of involutions (and why you might care), arXiv:1202.5319, 2012

Cf. A000041, A036039, A000085, A164342.

Needs["DiscreteMath`Combinatorica`"]; countinvolutions[cyclestructure_List]:= Times@@ ( (Plus@@ Table[(2k)!/k!/2^k Binomial[ #2,2k] #1^(#2-2k) #1^k,{k,0,#2/2}]&) @@@ ({First@#,Length@#}& /@ Split[cyclestructure]) ); Table[countinvolutions /@ Reverse/@ Sort[Sort/@ Partitions[n]],{n,10}]

Typo fixed by Franklin T. Adams-Watters, Aug 29 2009

A264753 Irregular triangle read by rows: T(n,k) = A127671(n,k)/A036040(n,k), n >= 1 and 1 <= k <= A000041(n).

Original entry on oeis.org

1, 1, -1, 1, -1, 2, 1, -1, -1, 2, -6, 1, -1, -1, 2, 2, -6, 24, 1, -1, -1, -1, 2, 2, 2, -6, -6, 24, -120, 1, -1, -1, -1, 2, 2, 2, 2, -6, -6, -6, 24, 24, -120, 720, 1, -1, -1, -1, -1, 2, 2, 2, 2, 2, -6, -6, -6, -6, -6, 24, 24, 24, -120, -120, 720, -5040

Offset: 1

Johannes W. Meijer, Jul 12 2016

This sequence connects the multinomial coefficients A036040 (M_3) with A127671 (M_5).
The numbers of terms in n-th row is the number of partitions A000041(n). The number of terms T(n, k) with equal values in the n-th row follow the rhythm of A008284(n).
Some row sums are [1, 0, 2, -5, 21, -104, 636, -4511, 36455, -330954, 3334390, -36914039].

			The first few rows of the T(n,k) triangle:
n = 1: 1
n = 2: 1, -1
n = 3: 1, -1, 2
n = 4: 1, -1, -1, 2, -6
n = 5: 1, -1, -1, 2, 2, -6, 24
n = 6: 1, -1, -1, -1, 2, 2, 2, -6, -6, 24, -120
n = 7: 1, -1, -1, -1, 2, 2, 2, 2, -6, -6, -6, 24, 24, -120, 720

Milton Abramowitz and Irene A. Stegun, editors, Multinomials: M_1, M_2 and M_3, Handbook of Mathematical Functions, December 1972, pp. 831-2.

Cf. A036040 (M_3), A127671 (M_5), A000041, A008284, A081362.

Cf. A048996 (M_0), A036038 (M_1), A036039 (M_2), A117506 (M_4).

nmax:=8: with(combinat): A008284 := proc(n, k) option remember; if k < 0 or n < 0 then 0 elif k = 0 then if n = 0 then 1 else 0 fi else A008284(n-1, k-1) + A008284(n-k, k) fi end: for n from 1 to nmax do p:=0: k:=1: while k < numbpart(n)+1 do p := p+1: k1 := A008284(n, p): while k1 > 0 do A264753(n, k) := (-1)^(p+1)*(p-1)!: k := k+1: k1 := k1-1: od: od: od: seq(seq(A264753(n, k), k = 1..numbpart(n)), n = 1..nmax);

nMax = 8; A008284[n_, k_] := A008284[n, k] = If[k<0 || n<0, 0, If[k == 0, If[n == 0, 1, 0], A008284[n-1, k-1] + A008284[n-k, k]]]; For[n = 1, n <= nMax, n++, p = 0; k = 1; While[k < PartitionsP[n]+1, p = p+1; k1 = A008284[n, p]; While[k1>0, A264753[n, k] = (-1)^(p+1)*(p-1)!; k = k+1; k1 = k1-1]]]; Table[Table[A264753[n, k], {k, 1, PartitionsP[n]}], {n, 1, nMax}] // Flatten (* Jean-François Alcover, Oct 01 2016, translated from Maple *)

T(n, k) = A127671(n, k)/A036040(n, k), n >= 1 and 1 <= k <= A000041(n).

A274541 Decimal expansion of exp(sqrt(2)/2).

Original entry on oeis.org

2, 0, 2, 8, 1, 1, 4, 9, 8, 1, 6, 4, 7, 4, 7, 2, 4, 5, 1, 1, 0, 8, 1, 2, 6, 1, 1, 2, 7, 4, 6, 3, 5, 1, 1, 7, 5, 1, 7, 4, 3, 2, 5, 0, 9, 2, 5, 4, 2, 6, 1, 3, 5, 2, 0, 6, 1, 7, 7, 7, 5, 9, 7, 2, 1, 2, 2, 2, 1, 5, 3, 9, 5, 0, 4, 8, 7, 1, 6, 5, 5, 9, 4, 2, 5, 9, 6

Offset: 1

Johannes W. Meijer, Jun 27 2016

Define P(n) = (1/n)*Sum_{k=0..n-1} x(n-k)*P(k), n >= 1 and P(0) = 1 with x(2) = (sqrt(2) + 1) and x(n) = 1 for all other n.
We find that C2 = lim_{n->infinity} P(n) = exp(sqrt(2)/2).
The structure of the n!*P(n) formulas leads to the multinomial coefficients A036039.

			c = 2.02811498164747245110812611274635117517432509254...

G. C. Greubel, Table of n, a(n) for n = 1..10000
The Dev Team and Simon Plouffe, The Inverse Symbolic Calculator (ISC).
Index entries for transcendental numbers

Cf. A274540, A274542, A014176, A010503, A036039.

SetDefaultRealField(RealField(100)); Exp[Sqrt[2]/2]; // G. C. Greubel, Aug 19 2018

Digits := 140: evalf(exp(sqrt(2)/2)); # End program 1.
P := proc(n) : if n=0 then 1 else P(n) := expand((1/n)*(add(x(n-k)*P(k), k=0..n-1))) fi; end: x := proc(n): if n=2 then (sqrt(2)+1) else 1 fi: end:
Digits := 140: evalf(P(250)); # End program 2.

First@ RealDigits@ N[Exp[Sqrt[2]/2], 83] (* Michael De Vlieger, Jun 27 2016 *)

my(x=exp(sqrt(2)/2)); for(k=1, 100, my(d=floor(x)); x=(x-d)*10; print1(d, ", ")) \\ Felix Fröhlich, Jun 27 2016

c = exp(sqrt(2)/2).

c = lim_{n->infinity} P(n), with P(n) = (1/n)*Sum_{k=0..n-1} x(n-k)*P(k), for n >= 1, and P(0) = 1, with x(2) = (1 + sqrt(2)), the silver mean A014176, and x(n) = 1 for all other n.

More digits from Jon E. Schoenfield, Mar 15 2018

A274542 Decimal expansion of exp(sqrt(2)/3).

Original entry on oeis.org

1, 6, 0, 2, 2, 4, 2, 9, 9, 7, 2, 0, 3, 5, 6, 0, 1, 5, 0, 9, 9, 5, 1, 7, 7, 7, 7, 2, 2, 2, 8, 6, 7, 8, 7, 5, 8, 5, 1, 2, 9, 6, 1, 6, 8, 2, 9, 5, 4, 5, 4, 7, 1, 8, 7, 4, 2, 6, 8, 2, 2, 4, 0, 5, 3, 0, 9, 1, 0, 0, 1, 6, 9, 9, 4, 9, 0, 4, 1, 9, 1, 9, 5, 8, 2

Offset: 1

Johannes W. Meijer, Jun 27 2016

Define P(n) = (1/n)*(sum(x(n-k)*P(k), k=0..n-1)), n >= 1 and P(0) =1 with x(3) = (1 + sqrt(2)) and x(n) = 1 for all other n. We find that C2 = limit(P(n), n -> infinity) = exp(sqrt(2)/3).

The structure of the n!*P(n) formulas leads to the multinomial coefficients A036039.

			c = 1.6022429972035601509951777722286787585129616829545471874……

G. C. Greubel, Table of n, a(n) for n = 1..10000
The Dev Team and Simon Plouffe, The Inverse Symbolic Calculator (ISC).
Index entries for transcendental numbers

Cf. A274540, A274541, A014176, A131594, A036039.

SetDefaultRealField(RealField(100)); Exp[Sqrt[2]/3]; // G. C. Greubel, Aug 19 2018

Digits := 85: evalf(exp(sqrt(2)/3)); # End program 1.
P := proc(n) : if n=0 then 1 else P(n) := expand((1/n)*(add(x(n-k)*P(k), k=0..n-1))) fi; end: x := proc(n): if n=3 then (sqrt(2)+1) else 1 fi: end: Digits := 56; evalf(P(120)); # End program 2.

First@ RealDigits@ N[Exp[Sqrt[2]/3], 85] (* Michael De Vlieger, Jun 27 2016 *)

my(x=exp(sqrt(2)/3)); for(k=1, 100, my(d=floor(x)); x=(x-d)*10; print1(d, ", ")) \\ Felix Fröhlich, Jun 27 2016

c = exp(sqrt(2)/3)

c = limit(P(n), n -> infinity) with P(n) = (1/n)*(sum(x(n-k)*P(k), k=0..n-1)) for n >= 1, and P(0) =1, with x(3) = (1 + sqrt(2)), the silver mean A014176, and x(n) = 1 for all other n.

A279038 Triangle of multinomial coefficients read by rows (ordered by decreasing size of the greatest part).

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 1, 6, 8, 3, 6, 1, 24, 30, 20, 20, 15, 10, 1, 120, 144, 90, 90, 40, 120, 40, 15, 45, 15, 1, 720, 840, 504, 504, 420, 630, 210, 280, 210, 420, 70, 105, 105, 21, 1, 5040, 5760, 3360, 3360, 2688, 4032, 1344, 1260, 3360, 1260, 2520, 420, 1120, 1120, 1680, 1120, 112, 105, 420, 210, 28, 1

Offset: 0

David W. Wilson and Olivier Gérard, Dec 04 2016

The ordering of integer partitions used in this version is also called:
- canonical ordering
- graded reverse lexicographic ordering
- magma (software) ordering
by opposition to the ordering used by Abramowitz and Stegun.

			First rows are:
    1
    1
    1   1
    2   3   1
    6   8   3   6   1
   24  30  20  20  15   10   1
  120 144  90  90  40  120  40  15  45  15  1
  720 840 504 504 420  630 210 280 210 420 70 105 105 21 1
  ...

Alois P. Heinz, Rows n = 0..28, flattened

Cf. A000041 (number of partitions of n, length of each row).
Cf. A128628 (triangle of partition lengths)
Cf. A036039 (a different ordering), A102189 (row reversed version of A036039).
Row sums give A000142.

b:= proc(n, i) option remember; `if`(n=0, [1],
      `if`(i<1, [], [seq(map(x-> x*i^j*j!,
       b(n-i*j, i-1))[], j=[iquo(n, i)-t$t=0..n/i])]))
    end:
T:= n-> map(x-> n!/x, b(n$2))[]:
seq(T(n), n=0..10);  # Alois P. Heinz, Dec 04 2016

Flatten[Table[
  Map[n!/Times @@ ((First[#]^Length[#]*Factorial[Length[#]]) & /@
        Split[#]) &, IntegerPartitions[n]], {n, 1, 8}]]
(* Second program: *)
b[n_, i_] := b[n, i] = If[n == 0, {1},
     If[i < 1, {}, Flatten@Table[#*i^j*j!& /@
     b[n - i*j, i - 1], {j, Quotient[n, i] - Range[0, n/i]}]]];
T[n_] := n!/#& /@ b[n, n];
T /@ Range[0, 10] // Flatten (* Jean-François Alcover, Jun 01 2021, after Alois P. Heinz *)

One term for row n=0 prepended by Alois P. Heinz, Dec 04 2016

cp's OEIS Frontend

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