A008485 -id:A008485 - cp's OEIS frontend

A252782 a(n) = n-th term of Euler transform of n-th powers.

1, 1, 5, 36, 490, 12729, 689896, 70223666, 13803604854, 5567490203192, 4386006155453382, 6711625359213752077, 21048250447828058144403, 131214686495783317936950378, 1603891839732647136012816743764, 40296598014204065945778862754895836

Offset: 0

Alois P. Heinz, Dec 21 2014

nonn

Alois P. Heinz, Table of n, a(n) for n = 0..80
Vaclav Kotesovec, Graph - The asymptotic ratio

Main diagonal of A144048.

Cf. A008485, A073229, A255672, A270917.

with(numtheory):
A:= proc(n, k) option remember; `if`(n=0, 1, add(add(
       d*d^k, d=divisors(j))*A(n-j, k), j=1..n)/n)
    end:
a:= n-> A(n$2):
seq(a(n), n=0..20);

Table[SeriesCoefficient[Product[1/(1-x^k)^(k^n),{k,1,n}],{x,0,n}], {n,0,20}] (* Vaclav Kotesovec, Mar 01 2015 *)

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

Conjecture: limit n->infinity a(n)^(1/n^2) = exp(exp(-1)) = 1.444667861... . - Vaclav Kotesovec, Mar 25 2016

A380290 a(n) = [x^n] G(x)^n, where G(x) = Product_{k >= 1} 1/(1 - x^k)^(k^2) is the g.f. of A023871.

Original entry on oeis.org

1, 1, 11, 73, 539, 3976, 30107, 229811, 1771803, 13749742, 107305836, 841211966, 6619647419, 52258136399, 413682035393, 3282569032273, 26101575743771, 207930807629248, 1659134361686186, 13258065574274885, 106084302933126364, 849845499077000534, 6815530442695480418, 54712839001004065090

Offset: 0

Peter Bala, Jan 19 2025

Given an integer sequence {f(n) : n >= 0} with f(0) = 1, there is a unique power series F(x) with rational coefficients, where F(0) = 1, such that f(n) = [x^n] F(x)^n. F(x) is given by F(x) = series_reversion(x/E(x)), where E(x) = exp(Sum_{n >= 1} f(n)*x^n/n). Furthermore, if the series E(x) has integer coefficients then the series F(x) also has integer coefficients and the sequence {f(n)} satisfies the Gauss congruences: f(n*p^r) == f(n*p^(r-1)) (mod p^r) for all primes p and positive integers n and r (by Stanley, Ch. 5, Ex. 5.2(a), p. 72 and the Lagrange inversion formula).
Thus the present sequence satisfies the Gauss congruences. In fact, stronger congruences appear to hold for the present sequence.
We conjecture that a(p) == 1 (mod p^3) for all primes p >= 7 (checked up to p = 61).
More generally, we conjecture that the supercongruence a(n*p^r) == a(n*p^(r-1)) (mod p^(3*r)) holds for all primes p >= 7 and positive integers n and r. Some examples are given below.

			Examples of supercongruences:
a(7) - a(1) = 229811 - 1 = 2*5*(7^3)*67 == 0 (mod 7^3)
a(3*7) - a(3) = 849845499077000534 - 73 = (7^3)*29243*84727410689 == 0 (mod 7^3)
a(19) - a(1) = 13258065574274885 - 1 = (2^2)*11*(19^3)*29*26723*56687 == 0 (mod 19^3)

R. P. Stanley. Enumerative combinatorics. Vol. 2, volume 62 of Cambridge Studies in Advanced Mathematics. Cambridge University Press, Cambridge, 1999.

Vaclav Kotesovec, Table of n, a(n) for n = 0..1000
Peter Bala, Notes on A380290 and A380291

Cf. A023871, A001158, A023873, A283263, A380291, A380581, A380582, A380583.

Cf. A008485, A255672, A386720.

with(numtheory):
G(x) := series(exp(add(sigma[3](k)*x^k/k, k = 1..23)),x,24):
seq(coeftayl(G(x)^n, x = 0, n), n = 0..23);

Table[SeriesCoefficient[Product[1/(1 - x^k)^(n*k^2), {k, 1, n}], {x, 0, n}], {n, 0, 25}] (* Vaclav Kotesovec, Jul 30 2025 *)
(* or *)
Table[SeriesCoefficient[Exp[n*Sum[DivisorSigma[3, k]*x^k/k, {k, 1, n}]], {x, 0, n}], {n, 0, 25}] (* Vaclav Kotesovec, Jul 30 2025 *)

a(n) = [x^n] exp(n*Sum_{k >= 1} sigma_3(k)*x^k/k).

a(n) ~ c * d^n / sqrt(n), where d = 8.20432131153340331179513077696629277558952852444670658917204305357709... and c = 0.2513708881073263860977360125648021910598660424705749139651716452651... - Vaclav Kotesovec, Jul 30 2025

A300974 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k^2))^n.

Original entry on oeis.org

1, 1, 3, 10, 39, 151, 588, 2304, 9111, 36307, 145553, 586246, 2370264, 9614242, 39105580, 159444160, 651468967, 2666771488, 10934393619, 44899828056, 184616878289, 760010818689, 3132147583744, 12921037206764, 53351800567200, 220478125956426, 911839751015196, 3773836780169050

Offset: 0

Ilya Gutkovskiy, Mar 17 2018

nonn

Number of partitions of n into squares of n kinds.

Cf. A000290, A001156, A008485, A023871, A240944, A279225, A285047, A300975, A301518.

a:= proc(m) option remember; local b; b:= proc(n, i)
      option remember; `if`(n=0, 1, `if`(i<1, 0, add(
      binomial(m+j-1, j)*b(n-i^2*j, i-1), j=0..n/i^2)))
      end: b(n, isqrt(n))
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Mar 17 2018

Table[SeriesCoefficient[Product[1/(1 - x^k^2)^n, {k, 1, n}], {x, 0, n}], {n, 0, 27}]

From Vaclav Kotesovec, Mar 23 2018: (Start)
a(n) ~ c * d^n / sqrt(n), where
d = 4.216358447600641565890184638418336163396695730036... and
c = 0.26442245016754864773722176155288663999776... (End)

A303070 a(n) = [x^n] (1/(1 - x))*Product_{k>=1} 1/(1 - x^k)^n.

Original entry on oeis.org

1, 2, 8, 35, 164, 787, 3857, 19147, 96004, 485009, 2465013, 12589315, 64555985, 332158127, 1714001409, 8866730665, 45968787524, 238778897128, 1242417984179, 6474394344503, 33784931507529, 176515163156311, 923265560495737, 4834081924982522, 25334170138318345, 132883719945537587

Offset: 0

Ilya Gutkovskiy, Apr 18 2018

nonn

Vaclav Kotesovec, Table of n, a(n) for n = 0..300
Index entries for sequences related to partitions

Main diagonal of A210764.

Cf. A000070, A000713, A008485, A144064, A210843.

Table[SeriesCoefficient[1/(1 - x) Product[1/(1 - x^k)^n, {k, 1, n}], {x, 0, n}], {n, 0, 25}]
Table[SeriesCoefficient[1/(1 - x) Exp[n Sum[x^k/(k (1 - x^k)), {k, 1, n}]], {x, 0, n}], {n, 0, 25}]

a(n) = [x^n] (1/(1 - x))*exp(n*Sum_{k>=1} x^k/(k*(1 - x^k))).
a(n) = A210764(n,n) = Sum_{j=0..n} A144064(j,n).
a(n) ~ c * d^n / sqrt(n), where d = A270915 = 5.352701333486642687772415814165... and c = 0.4068869940800214657298372785820... - Vaclav Kotesovec, May 19 2018

A304444 Coefficient of x^n in Product_{k>=1} 1/(1-x^k)^(2*n).

Original entry on oeis.org

1, 2, 14, 98, 726, 5512, 42614, 333608, 2636326, 20985272, 168012824, 1351507830, 10914317934, 88432329546, 718545161208, 5852747363518, 47774241056710, 390702055798978, 3200542803221192, 26257321971526646, 215705170816632376, 1774181109262878848

Offset: 0

Vaclav Kotesovec, May 12 2018

nonn

Vaclav Kotesovec, Table of n, a(n) for n = 0..1000

Cf. A000712, A008485, A161870, A171803, A304443.

nmax = 25; Table[SeriesCoefficient[Product[1/(1-x^k)^(2*n), {k, 1, n}], {x, 0, n}], {n, 0, nmax}]
nmax = 25; Table[SeriesCoefficient[1/QPochhammer[x]^(2*n), {x, 0, n}], {n, 0, nmax}]
(* Calculation of constants {d,c}: *) eq = FindRoot[{1/QPochhammer[r*s]^2 == s, 1/s + 2*r*Sqrt[s]*Derivative[0, 1][QPochhammer][r*s, r*s] == (2*(Log[1 - r*s] + QPolyGamma[0, 1, r*s]))/(s* Log[r*s])}, {r, 1/8}, {s, 2}, WorkingPrecision -> 1000]; {N[1/r /. eq, 120], val = Sqrt[((1 - r*s)*Log[r*s]^2)/(Pi*(16*r*s*ArcTanh[1 - 2*r*s] - (-1 + r*s)*(Log[r*s] - 2*Log[1 - r*s])*(3*Log[r*s] - 2*Log[1 - r*s]) - 8*Log[1 - r*s] - 8*(-1 + r*s)*(-1 + 2*ArcTanh[1 - 2*r*s])* QPolyGamma[0, 1, r*s] + (4 - 4*r*s)* QPolyGamma[0, 1, r*s]^2 + 4*(-1 + r*s)*(QPolyGamma[1, 1, r*s] + r*s*Log[r*s] * (r*s^(3/2)*Log[r*s]* Derivative[0, 2][QPochhammer][r*s, r*s] - 2*Derivative[0, 0, 1][QPolyGamma][0, 1, r*s]))))] /. eq; N[Chop[val], -Floor[Log[10, Abs[Im[val]]]] - 3]} (* Vaclav Kotesovec, Oct 03 2023 *)

a(n) ~ c * d^n / sqrt(n), where d = 8.42516721063251541777601555584151410936132980324698494327338254953123205... and c = 0.29923152009652750283923119244187982714171590056794904644563876...

A296163 a(n) = [x^n] Product_{k>=1} ((1 - x^(5*k))/(1 - x^k))^n.

Original entry on oeis.org

1, 1, 5, 22, 105, 501, 2456, 12160, 60801, 306130, 1550255, 7887034, 40281720, 206405967, 1060602800, 5463059772, 28199365873, 145832364580, 755420838614, 3918935839970, 20357605331355, 105878815699042, 551273881133750, 2873161931172668, 14988243880188600

Offset: 0

Ilya Gutkovskiy, Dec 06 2017

nonn

Eric Weisstein's World of Mathematics, Partition Function b_k

Cf. A008485, A035959, A121591, A263002, A270913, A285928, A296044, A296162.

Table[SeriesCoefficient[Product[((1 - x^(5 k))/(1 - x^k))^n, {k, 1, n}], {x, 0, n}], {n, 0, 24}]
Table[SeriesCoefficient[Product[(1 + x^k + x^(2 k) + x^(3 k) + x^(4 k))^n, {k, 1, n}], {x, 0, n}], {n, 0, 24}]
(* Calculation of constant d: *) With[{k = 5}, 1/r /. FindRoot[{s == QPochhammer[(r*s)^k] / QPochhammer[r*s], k*(-(s*QPochhammer[r*s]*(Log[1 - (r*s)^k] + QPolyGamma[0, 1, (r*s)^k]) / Log[(r*s)^k]) + (r*s)^k * Derivative[0, 1][QPochhammer][(r*s)^k, (r*s)^k]) == s*QPochhammer[r*s] + s^2*(-(QPochhammer[r*s]*(Log[1 - r*s] + QPolyGamma[0, 1, r*s]) / (s*Log[r*s])) + r*Derivative[0, 1][QPochhammer][r*s, r*s])}, {r, 1/5}, {s, 1}, WorkingPrecision -> 70]] (* Vaclav Kotesovec, Jan 17 2024 *)

a(n) = [x^n] Product_{k>=1} (1 + x^k + x^(2*k) + x^(3*k) + x^(4*k))^n.

a(n) ~ c * d^n / sqrt(n), where d = 5.3271035802753567624196808294779171420899175782347488197... and c = 0.2712048688090020853684153670711011713396954... - Vaclav Kotesovec, May 13 2018

A300975 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k^3))^n.

Original entry on oeis.org

1, 1, 3, 10, 35, 126, 462, 1716, 6443, 24391, 92928, 355862, 1368458, 5280744, 20438148, 79302960, 308385355, 1201536286, 4689450021, 18330233110, 71747534460, 281177705490, 1103163479190, 4332522733560, 17031238725410, 67007449610751, 263841039245280, 1039628691988795

Offset: 0

Ilya Gutkovskiy, Mar 17 2018

nonn

Number of partitions of n into cubes of n kinds.

Cf. A000578, A003108, A008485, A023872, A298434, A300974.

a:= proc(m) option remember; local b; b:= proc(n, i)
      option remember; `if`(n=0, 1, `if`(i<1, 0, add(
      binomial(m+j-1, j)*b(n-i^3*j, i-1), j=0..n/i^3)))
      end: b(n, iroot(n, 3))
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Mar 17 2018

Table[SeriesCoefficient[Product[1/(1 - x^k^3)^n, {k, 1, n}], {x, 0, n}], {n, 0, 27}]

a(n) ~ c * d^n / sqrt(n), where d = 4.0147940395164236614815683662796167488... and c = 0.2726202310726337579308600184572222... - Vaclav Kotesovec, Mar 23 2018

A304446 Coefficient of x^n in Product_{k>=1} 1/(1-x^k)^(n^2).

Original entry on oeis.org

1, 1, 14, 255, 6460, 209405, 8287038, 387605491, 20930373880, 1281932464680, 87828985857380, 6656774777650459, 553068813860022264, 49988877225605011590, 4883606791114233989450, 512829418039842285746460, 57607740718731604241384432, 6893420862444517638234527039

Offset: 0

Vaclav Kotesovec, May 12 2018

nonn

Vaclav Kotesovec, Table of n, a(n) for n = 0..330

Cf. A008485, A023871, A304445.

nmax = 20; Table[SeriesCoefficient[Product[1/(1-x^k)^(n^2), {k, 1, n}], {x, 0, n}], {n, 0, nmax}]
nmax = 20; Table[SeriesCoefficient[1/QPochhammer[x]^(n^2), {x, 0, n}], {n, 0, nmax}]

a(n) ~ exp(n + 3/2) * n^(n - 1/2) / sqrt(2*Pi).

A192435 Number of terms in n-th derivative of a function composed with itself n times.

Original entry on oeis.org

1, 2, 6, 26, 110, 532, 2541, 12644, 63024, 318857, 1618947, 8277062, 42453073, 218597485, 1128527057, 5841301830, 30297014746, 157442596130, 819511659381, 4272054888643, 22299423992018, 116539878029773, 609718298887977, 3193136462042241, 16737951567806110

Offset: 1

Alois P. Heinz, Aug 18 2012

nonn

Alois P. Heinz, Table of n, a(n) for n = 1..600
W. C. Yang, Derivatives are essentially integer partitions, Discrete Mathematics, 222(1-3), July 2000, 235-245.

Main diagonal of A022818.

Cf. A008485.

A:= proc(n, k) option remember;
      `if`(k=1, 1, add(b(n, n, i)*A(i, k-1), i=0..n))
    end:
b:= proc(n, i, k) option remember; `if`(n A(n, n):
seq(a(n), n=1..40);

A[n_, k_] := A[n, k] = If[k == 1, 1, Sum[b[n, n, i]*A[i, k-1], {i, 0, n}]]; b[n_, i_, k_] := b[n, i, k] = If[nJean-François Alcover, Feb 05 2015, after Alois P. Heinz *)

a(n) ~ c * d^n / sqrt(n), where d = A270915 = 5.35270133348664..., c = 0.0504640078963302151598181537452... . - Vaclav Kotesovec, Sep 03 2014, updated May 19 2018

A304625 a(n) = [x^n] Product_{k>=1} ((1 - x^(n*k))/(1 - x^k))^n.

Original entry on oeis.org

1, 0, 3, 19, 101, 501, 2486, 12398, 62329, 315436, 1605330, 8207552, 42124368, 216903051, 1119974861, 5796944342, 30068145889, 156250892593, 813310723907, 4239676354631, 22130265931880, 115654632452514, 605081974091853, 3168828466966365, 16610409114771876, 87141919856550506

Offset: 0

Ilya Gutkovskiy, May 15 2018

nonn

Number of partitions of n into 2 or more parts of n kinds. - Ilya Gutkovskiy, May 16 2018

Index entries for sequences related to partitions

Cf. A000065, A008485, A022567, A093160, A270913, A285927, A285928, A286653, A296044, A296162, A296163, A304626.

Table[SeriesCoefficient[Product[((1 - x^(n k))/(1 - x^k))^n, {k, 1, n}], {x, 0, n}], {n, 0, 25}]
Table[SeriesCoefficient[Product[1/(1 - x^k)^n, {k, 1, n - 1}], {x, 0, n}], {n, 0, 25}]

a(n) ~ c * d^n / sqrt(n), where d = A270915 = 5.3527013334866426877724... and c = 0.268015212710733315686... - Vaclav Kotesovec, May 16 2018

cp's OEIS Frontend

A252782 a(n) = n-th term of Euler transform of n-th powers.

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A380290 a(n) = [x^n] G(x)^n, where G(x) = Product_{k >= 1} 1/(1 - x^k)^(k^2) is the g.f. of A023871.

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A300974 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k^2))^n.

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A303070 a(n) = [x^n] (1/(1 - x))*Product_{k>=1} 1/(1 - x^k)^n.

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A304444 Coefficient of x^n in Product_{k>=1} 1/(1-x^k)^(2*n).

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A296163 a(n) = [x^n] Product_{k>=1} ((1 - x^(5*k))/(1 - x^k))^n.

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A300975 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k^3))^n.

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A304446 Coefficient of x^n in Product_{k>=1} 1/(1-x^k)^(n^2).

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