A008637 -id:A008637 - cp's OEIS frontend

A026820 Euler's table: triangular array T read by rows, where T(n,k) = number of partitions in which every part is <= k for 1 <= k <= n. Also number of partitions of n into at most k parts.

1, 1, 2, 1, 2, 3, 1, 3, 4, 5, 1, 3, 5, 6, 7, 1, 4, 7, 9, 10, 11, 1, 4, 8, 11, 13, 14, 15, 1, 5, 10, 15, 18, 20, 21, 22, 1, 5, 12, 18, 23, 26, 28, 29, 30, 1, 6, 14, 23, 30, 35, 38, 40, 41, 42, 1, 6, 16, 27, 37, 44, 49, 52, 54, 55, 56, 1, 7, 19, 34, 47, 58, 65, 70, 73, 75, 76, 77

Offset: 1

Clark Kimberling

			Triangle starts:
  1;
  1, 2;
  1, 2,  3;
  1, 3,  4,  5;
  1, 3,  5,  6,  7;
  1, 4,  7,  9, 10, 11;
  1, 4,  8, 11, 13, 14, 15;
  1, 5, 10, 15, 18, 20, 21, 22;
  1, 5, 12, 18, 23, 26, 28, 29, 30;
  1, 6, 14, 23, 30, 35, 38, 40, 41, 42;
  1, 6, 16, 27, 37, 44, 49, 52, 54, 55, 56;
  ...

G. Chrystal, Algebra, Vol. II, p. 558.
D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, Section XIV.2, p. 493.

Alois P. Heinz, Robert G. Wilson v, Rows n = 1..141, flattened
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972, p. 831. [scanned copy]
Carolyn Echter, Georg Maier, Juan-Diego Urbina, Caio Lewenkopf, and Klaus Richter, Many-body density of states of bosonic and fermionic gases: a combinatorial approach, arXiv:2409.08696 [cond-mat.quant-gas], 2024. See p. 10.
L. Euler, Introductio in Analysin Infinitorum, Book I, chapter XVI.
T. S. Motzkin, Sorting numbers for cylinders and other classification numbers, in Combinatorics, Proc. Symp. Pure Math. 19, AMS, 1971, pp. 167-176. [Annotated, scanned copy]
OEIS Wiki, Sorting numbers.
R. Sulzgruber, The Symmetry of the q,t-Catalan Numbers, Masterarbeit, Univ. Wien, 2013.
Sergei Viznyuk, C program.
Sergei Viznyuk, Local copy of C program.
Eric Weisstein's World of Mathematics, Partition Function q.
Index entries for sequences related to partitions - _Reinhard Zumkeller_, Jan 21 2010

Partial sums of rows of A008284, row sums give A058397, central terms give A171985, mirror is A058400.
T(n,n) = A000041(n), T(n,1) = A000012(n), T(n,2) = A008619(n) for n>1, T(n,3) = A001399(n) for n>2, T(n,4) = A001400(n) for n>3, T(n,5) = A001401(n) for n>4, T(n,6) = A001402(n) for n>5, T(n,7) = A008636(n) for n>6, T(n,8) = A008637(n) for n>7, T(n,9) = A008638(n) for n>8, T(n,10) = A008639(n) for n>9, T(n,11) = A008640(n) for n>10, T(n,12) = A008641(n) for n>11, T(n,n-2) = A007042(n-1) for n>2, T(n,n-1) = A000065(n) for n>1.
Cf. A008284, A026840, A134737, A173519.

import Data.List (inits)
a026820 n k = a026820_tabl !! (n-1) !! (k-1)
a026820_row n = a026820_tabl !! (n-1)
a026820_tabl = zipWith
   (\x -> map (p x) . tail . inits) [1..] $ tail $ inits [1..] where
   p 0 _ = 1
   p _ [] = 0
   p m ks'@(k:ks) = if m < k then 0 else p (m - k) ks' + p m ks
-- Reinhard Zumkeller, Dec 18 2013

T:= proc(n, k) option remember;
      `if`(n=0 or k=1, 1, T(n, k-1) + `if`(k>n, 0, T(n-k, k)))
    end:
seq(seq(T(n, k), k=1..n), n=1..12); # Alois P. Heinz, Apr 21 2012

t[n_, k_] := Length@ IntegerPartitions[n, k]; Table[ t[n, k], {n, 12}, {k, n}] // Flatten
(* Second program: *)
T[n_, k_] := T[n, k] = If[n==0 || k==1, 1, T[n, k-1] + If[k>n, 0, T[n-k, k]]]; Table[T[n, k], {n, 1, 12}, {k, 1, n}] // Flatten (* Jean-François Alcover, Sep 22 2015, after Alois P. Heinz *)

T(n,k)=my(s); forpart(v=n,s++,,k); s \\ Charles R Greathouse IV, Feb 27 2018

from sage.combinat.partition import number_of_partitions_length
from itertools import accumulate
for n in (1..11):
    print(list(accumulate([number_of_partitions_length(n, k) for k in (1..n)])))
# Peter Luschny, Jul 28 2022

T(T(n,n),n) = A134737(n). - Reinhard Zumkeller, Nov 07 2007
T(A000217(n),n) = A173519(n). - Reinhard Zumkeller, Feb 20 2010
T(n,k) = T(n,k-1) + T(n-k,k). - Thomas Dybdahl Ahle, Jun 13 2011
T(n,k) = Sum_{i=1..min(k,floor(n/2))} T(n-i,i) + Sum_{j=1+floor(n/2)..k} A000041(n-j). - Bob Selcoe, Aug 22 2014 [corrected by Álvar Ibeas, Mar 15 2018]
O.g.f.: Product_{i>=0} 1/(1-y*x^i). - Geoffrey Critzer, Mar 11 2012
T(n,k) = A008284(n+k,k). - Álvar Ibeas, Jan 06 2015

A236810 Number of solutions to Sum_{k=1..n} k*c(k) = n! , c(k) >= 0.

Original entry on oeis.org

0, 1, 2, 7, 169, 91606, 2407275335, 4592460368601183, 855163933625625205568537, 20560615981766266405801870502139241, 82864945825700191674729490954631752385038099201, 70899311833745096407560015806403481692583415598602691709750081

Offset: 0

Wouter Meeussen, Feb 08 2014

nonn

a(n) is the number of partitions of n! into parts that are at most n. a(3) = 7: [1,1,1,1,1,1], [2,1,1,1,1], [2,2,1,1], [2,2,2], [3,1,1,1], [3,2,1], [3,3]. - Alois P. Heinz, Feb 08 2014

			for n=3, the 7 solutions are: 3! = 6,0,0 ; 4,1,0 ; 2,2,0 ; 0,3,0 ; 3,0,1 ; 1,1,1 ; 0,0,2.

Alois P. Heinz, Table of n, a(n) for n = 0..31
P. F. Ayuso, J. M. Grau, A. Oller-Marcen, Von Staudt formula for Sum_{z in Z_n[i]} z^k, arXiv preprint arXiv:1402.0333, 2014, Montsh. Math. 178 (2015) 345-359
Vaclav Kotesovec, Graph - the asymptotic ratio (Total 90 terms were computed with a program by Doron Zeilberger)
A. V. Sills and D. Zeilberger, Formulae for the number of partitions of n into at most m parts (using the quasi-polynomial ansatz), arXiv:1108.4391 [math.CO], Dec 2011
StackExchange, Combinations sum_{k=1..m} k*n_k = m!, Jan 29 2014

Cf. A008290, A008637, A237512, A258668, A258669, A258670, A258671.

Table[Coefficient[Series[Product[1/(1- x^k),{k,n}],{x,0,n!}],x^(n!)] ,{n,7}]

a(n) = [x^(n!)] Product_{k=1..n} 1/(1-x^k).

a(n) ~ n * (n!)^(n-3) ~ n^(n^2-5*n/2-1/2) * (2*Pi)^((n-3)/2) / exp(n*(n-3)-1/12). - Vaclav Kotesovec, Jun 05 2015

a(8)-a(11) from Alois P. Heinz, Feb 08 2014

A008638 Number of partitions of n into at most 9 parts.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 41, 54, 73, 94, 123, 157, 201, 252, 318, 393, 488, 598, 732, 887, 1076, 1291, 1549, 1845, 2194, 2592, 3060, 3589, 4206, 4904, 5708, 6615, 7657, 8824, 10156, 11648, 13338, 15224, 17354, 19720, 22380, 25331, 28629, 32278

Offset: 0

N. J. A. Sloane

For n > 8: also number of partitions of n into parts <= 9: a(n) = A026820(n, 9). - Reinhard Zumkeller, Jan 21 2010

A. Cayley, Collected Mathematical Papers. Vols. 1-13, Cambridge Univ. Press, London, 1889-1897, Vol. 10, p. 415.
H. Gupta et al., Tables of Partitions. Royal Society Mathematical Tables, Vol. 4, Cambridge Univ. Press, 1958, p. 2.

T. D. Noe, Table of n, a(n) for n = 0..1000
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 358
Index entries for related partition-counting sequences
Index entries for linear recurrences with constant coefficients, signature (1,1,0,0,-1,0,-1,0,0,-1,0,2,1,1,1,0, -1,-1,-1,-2,-1,-1,1,1,2,1,1,1,0, -1,-1,-1,-2,0,1,0,0,1,0,1,0,0,-1,-1,1)

Essentially same as A026815.
a(n) = A008284(n+9, 9), n >= 0.
Cf. A288344 (partial sums), A266777 (first differences).

CoefficientList[ Series[ 1/ Product[ 1 - x^n, {n, 1, 9} ], {x, 0, 60} ], x ]

G.f.: 1/Product_{k=1..9} (1 - q^k).
a(n) = floor((30*n^8 + 5400*n^7 + 405300*n^6 + 16443000*n^5 + 390533640*n^4 + 5486840100*n^3 + 43691213950*n^2 + 175052776500*n + 256697834389)/438939648000 + (n + 1)*(2*n^2 + 133*n + 2597)*(-1)^n/147456 + (-1)^n*((n + 1)*(n + 47)*(-1)^floor(n/3 + 2/3) + (2*n^2 + 90*n + 127)*(-1)^floor(n/3 + 1/3) + (n + 2)*(n + 40)*(-1)^floor(n/3))/17496 + 1/256*((-1)^((2*n + (-1)^n - 1)/4)*floor((n + 2)/2)) + 1/2). - Tani Akinari, Oct 20 2012
a(n) = a(n-9) + A008637(n). - Vladimír Modrák, Sep 28 2020
From Vladimír Modrák, Aug 09 2022: (Start)
a(n) = Sum_{i_1=0..floor(n/3)} Sum_{i_2=0..floor(n/4)} Sum_{i_3=0..floor(n/5)} Sum_{i_4=0..floor(n/6)} Sum_{i_5=0..floor(n/7)} Sum_{i_6=0..floor(n/8)} Sum_{i_7=0..floor(n/9)} ceiling((max(0, n + 1 - 3*i_1 - 4*i_2 - 5*i_3 - 6*i_4 - 7*i_5 - 8*i_6 - 9*i_7))/2).
a(n) = Sum_{i_1=0..floor(n/4)} Sum_{i_2=0..floor(n/5)} Sum_{i_3=0..floor(n/6)} Sum_{i_4=0..floor(n/7)} Sum_{i_5=0..floor(n/8)} Sum_{i_6=0..floor(n/9)} floor(((max(0, n + 3 - 4*i_1 - 5*i_2 - 6*i_3 - 7*i_4 - 8*i_5 - 9*i_6))^2+4)/12). (End)

A347544 Number of partitions of n into 8 or more parts.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 30, 45, 67, 96, 137, 190, 263, 356, 480, 637, 842, 1098, 1427, 1835, 2351, 2986, 3780, 4749, 5949, 7405, 9190, 11344, 13966, 17111, 20913, 25454, 30908, 37393, 45141, 54315, 65222, 78090, 93317, 111220, 132323, 157050, 186088, 220015, 259716

Offset: 8

Ilya Gutkovskiy, Sep 06 2021

nonn

Cf. A000065, A004250, A008637, A035300, A035301, A347542, A347543, A347545, A347547.

nmax = 52; CoefficientList[Series[Sum[x^k/Product[(1 - x^j), {j, 1, k}], {k, 8, nmax}], {x, 0, nmax}], x] // Drop[#, 8] &

G.f.: Sum_{k>=8} x^k / Product_{j=1..k} (1 - x^j).

A008631 Molien series for alternating group Alt_8 (or A_8).

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 29, 40, 52, 70, 89, 116, 146, 186, 230, 288, 352, 434, 525, 638, 764, 919, 1090, 1297, 1527, 1802, 2105, 2464, 2860, 3324, 3835, 4428, 5081, 5834, 6659, 7604, 8640, 9819, 11107, 12566, 14158, 15951, 17904, 20093, 22474, 25133

Offset: 0

N. J. A. Sloane

D. J. Benson, Polynomial Invariants of Finite Groups, Cambridge, 1993, p. 105.

G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for Molien series
Index entries for linear recurrences with constant coefficients, signature (1,1,0,1,-2,-1,-1,-1,1,1,2,3,0,-1,-1,-4,-1,-1,0,3,2,1,1,-1,-1,-1,-2,1,0,1,1,-1).

Different from A008637.

R:=PowerSeriesRing(Integers(), 50); Coefficients(R!( (1+x^28)/(&*[1-x^j: j in [1..8]]) )); // G. C. Greubel, Feb 02 2020

seq(coeff(series( (1+x^28)/mul((1-x^j), j=1..8)), x, n+1), x, n), n = 0..50); # G. C. Greubel, Feb 02 2020

CoefficientList[Series[(1+x^28)/Product[(1-x^j), {j,1,8}], {x,0,50}], x] (* G. C. Greubel, Feb 02 2020 *)
LinearRecurrence[{1,1,0,1,-2,-1,-1,-1,1,1,2,3,0,-1,-1,-4,-1,-1,0,3,2,1,1,-1,-1,-1,-2,1,0,1,1,-1},{1,1,2,3,5,7,11,15,22,29,40,52,70,89,116,146,186,230,288,352,434,525,638,764,919,1090,1297,1527,1802,2105,2464,2860},70] (* Harvey P. Dale, May 12 2022 *)

Vec( (1+x^28)/prod(j=1,8, 1-x^j) +O('x^50) ) \\ G. C. Greubel, Feb 02 2020

def A008631_list(prec):
    P. = PowerSeriesRing(ZZ, prec)
    return P( (1+x^28)/product(1-x^j for j in (1..8)) ).list()
A008631_list(70) # G. C. Greubel, Feb 02 2020

G.f.: (1+x^28)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5)*(1-x^6)*(1-x^7)*(1-x^8)).

cp's OEIS Frontend

A026820 Euler's table: triangular array T read by rows, where T(n,k) = number of partitions in which every part is <= k for 1 <= k <= n. Also number of partitions of n into at most k parts.

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A236810 Number of solutions to Sum_{k=1..n} k*c(k) = n! , c(k) >= 0.

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A008638 Number of partitions of n into at most 9 parts.

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A347544 Number of partitions of n into 8 or more parts.

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A008631 Molien series for alternating group Alt_8 (or A_8).

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