cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A117148 Number of parts in all partitions of n in which no part occurs more than 3 times.

Original entry on oeis.org

1, 3, 6, 8, 15, 24, 36, 50, 75, 102, 143, 197, 264, 349, 467, 606, 789, 1016, 1299, 1656, 2100, 2634, 3302, 4117, 5106, 6306, 7772, 9523, 11639, 14185, 17216, 20839, 25166, 30280, 36361, 43551, 52022, 62004, 73753, 87510, 103638, 122507, 144496, 170133
Offset: 1

Views

Author

Emeric Deutsch, Mar 07 2006

Keywords

Comments

a(n) = sum(A117147(n,k), k>=1).

Examples

			a(4) = 8 because the partitions of 4 in which no part occurs more than 3 times are [4], [3,1], [2,2] and [2,1,1] ([1,1,1,1] does not qualify) with a total of 1+2+2+3=8 parts.
		

Crossrefs

Column k=3 of A210485. - Alois P. Heinz, Jan 23 2013

Programs

  • Maple
    g:=product(1+x^j+x^(2*j)+x^(3*j),j=1..55) *sum((x^j+2*x^(2*j)+3*x^(3*j))/ (1+x^j+x^(2*j)+x^(3*j)), j=1..55): gser:=series(g,x=0,53): seq(coeff(gser,x^n),n=1..50);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<1, [0, 0],
          add((l->[l[1], l[2]+l[1]*j])(b(n-i*j, i-1)), j=0..min(n/i, 3))))
        end:
    a:= n-> b(n, n)[2]:
    seq(a(n), n=1..50);  # Alois P. Heinz, Jan 08 2013
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, {1, 0}, If[i<1, {0, 0}, Sum[Function[{l}, {l[[1]], l[[2]] + l[[1]]*j}][b[n-i*j, i-1]], {j, 0, Min[n/i, 3]}]]]; a[n_] := b[n, n][[2]]; Table[a[n], {n, 1, 50}] (* Jean-François Alcover, May 26 2015, after Alois P. Heinz *)

Formula

G.f.: product(1+x^j+x^(2j)+x^(3j), j=1..infinity) * sum((x^j+2x^(2j)+3x^(3j)) / (1+x^j+x^(2j)+x^(3j)), j=1..infinity).
a(n) ~ log(2) * exp(Pi*sqrt(n/2)) / (Pi * 2^(1/4) * n^(1/4)). - Vaclav Kotesovec, May 27 2018

A295831 Expansion of Product_{k>=1} ((1 + x^(2*k))/(1 - x^(2*k-1)))^k.

Original entry on oeis.org

1, 1, 2, 4, 6, 11, 19, 30, 47, 76, 118, 181, 277, 417, 624, 929, 1367, 2001, 2913, 4210, 6056, 8665, 12328, 17466, 24640, 34600, 48395, 67442, 93625, 129520, 178588, 245429, 336252, 459324, 625613, 849762, 1151150, 1555378, 2096332, 2818630, 3780903, 5060240, 6757633, 9005106, 11975265
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 28 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 44; CoefficientList[Series[Product[((1 + x^(2 k))/(1 - x^(2 k - 1)))^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 44; CoefficientList[Series[Exp[Sum[x^k (1 - (-1)^k x^k)/(k (1 - x^(2 k))^2), {k, 1, nmax}]], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} ((1 + x^(2*k))/(1 - x^(2*k-1)))^k.
G.f.: exp(Sum_{k>=1} x^k*(1 - (-1)^k*x^k)/(k*(1 - x^(2*k))^2)).
a(n) ~ exp(3*(7*Zeta(3))^(1/3) * n^(2/3) / 4 + Pi^2 * n^(1/3) / (12 * (7*Zeta(3))^(1/3)) - Pi^4 / (3024*Zeta(3)) - 1/24) * A^(1/2) * (7*Zeta(3))^(11/72) / (2^(11/8) * sqrt(3*Pi) * n^(47/72)), where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Nov 28 2017

A327045 Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)).

Original entry on oeis.org

1, 1, 2, 4, 5, 8, 13, 17, 24, 36, 47, 64, 89, 115, 152, 204, 260, 336, 438, 552, 702, 896, 1117, 1400, 1758, 2171, 2688, 3332, 4079, 5000, 6131, 7446, 9048, 10992, 13255, 15984, 19264, 23081, 27644, 33084, 39408, 46912, 55797, 66107, 78264, 92572, 109140
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 16 2019

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^k) * (1+x^(2*k)) * (1+x^(3*k)), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ 11^(1/4) * exp(sqrt(11*n/2)*Pi/3) / (2^(13/4)*sqrt(3)*n^(3/4)).

A327046 Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)) * (1 + x^(4*k)).

Original entry on oeis.org

1, 1, 2, 4, 6, 9, 15, 21, 30, 45, 62, 85, 120, 161, 216, 293, 385, 505, 667, 862, 1112, 1438, 1833, 2330, 2965, 3733, 4688, 5887, 7334, 9114, 11319, 13970, 17203, 21162, 25905, 31643, 38605, 46911, 56891, 68904, 83179, 100224, 120603, 144719, 173360, 207396
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 16 2019

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^k) * (1+x^(2*k)) * (1+x^(3*k)) * (1+x^(4*k)), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ sqrt(5) * exp(5*Pi*sqrt(n)/6) / (16*sqrt(3)*n^(3/4)).

A327047 Expansion of Product_{k>=1} (1 + x^k) * (1 + x^(2*k)) * (1 + x^(3*k)) * (1 + x^(4*k)) * (1 + x^(5*k)).

Original entry on oeis.org

1, 1, 2, 4, 6, 10, 16, 23, 34, 51, 72, 101, 143, 195, 267, 366, 487, 650, 866, 1135, 1487, 1940, 2504, 3226, 4145, 5283, 6714, 8513, 10725, 13481, 16905, 21085, 26244, 32588, 40299, 49732, 61229, 75131, 92004, 112435, 137009, 166627, 202269, 244919, 296038
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 16 2019

Keywords

Comments

In general, for fixed m>=1, if g.f. = Product_{k>=1} (Product_{j=1..m} (1 + x^(j*k))), then a(n) ~ HarmonicNumber(m)^(1/4) * exp(Pi*sqrt(HarmonicNumber(m)*n/3)) / (2^((m+3)/2) * 3^(1/4) * n^(3/4)).

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[(1+x^k) * (1+x^(2*k)) * (1+x^(3*k)) * (1+x^(4*k)) * (1+x^(5*k)), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

a(n) ~ 137^(1/4) * exp(sqrt(137*n/5)*Pi/6) / (2^(9/2)*sqrt(3)*5^(1/4)*n^(3/4)).

A098491 Number of partitions of n with parts occurring at most thrice and an even number of parts. Row sums of A098489.

Original entry on oeis.org

1, 0, 1, 1, 2, 3, 5, 6, 8, 11, 15, 19, 25, 32, 41, 52, 66, 83, 104, 129, 160, 197, 242, 296, 361, 438, 530, 640, 770, 923, 1105, 1318, 1569, 1864, 2208, 2611, 3082, 3628, 4264, 5003, 5858, 6848, 7993, 9312, 10833, 12584, 14595, 16904, 19552, 22582, 26049
Offset: 0

Views

Author

Ralf Stephan, Sep 12 2004

Keywords

Crossrefs

Equals A001935 - A098492. Differs from A098492 at triangular indices.

Formula

a(n) = (A001935(n)+(-1)^n*A010054(n))/2. - Vladeta Jovovic, Sep 16 2004

Extensions

More terms from Vladeta Jovovic, Sep 16 2004

A098492 Number of partitions of n with parts occurring at most thrice and an odd number of parts. Row sums of A098490.

Original entry on oeis.org

0, 1, 1, 2, 2, 3, 4, 6, 8, 11, 14, 19, 25, 32, 41, 53, 66, 83, 104, 129, 160, 198, 242, 296, 361, 438, 530, 640, 769, 923, 1105, 1318, 1569, 1864, 2208, 2611, 3081, 3628, 4264, 5003, 5858, 6848, 7993, 9312, 10833, 12585, 14595, 16904, 19552, 22582, 26049
Offset: 0

Views

Author

Ralf Stephan, Sep 12 2004

Keywords

Crossrefs

Equals A001935 - A098491. Differs from A098491 at triangular indices.

Formula

a(n) = (A001935(n)-(-1)^n*A010054(n))/2. - Vladeta Jovovic, Sep 16 2004

A177155 G.f.: exp( Integral (theta_3(x)^8-1)/(16x) dx ), where theta_3(x) = 1 + Sum_{n>=1} 2*x^(n^2) is a Jacobi theta function.

Original entry on oeis.org

1, 1, 4, 13, 35, 87, 217, 539, 1291, 2999, 6880, 15595, 34738, 76202, 165282, 354655, 752546, 1580514, 3289337, 6787085, 13887937, 28195434, 56824772, 113729640, 226104615, 446665922, 877063515, 1712252521, 3324245063, 6419561961
Offset: 0

Views

Author

Paul D. Hanna, May 03 2010, May 08 2010

Keywords

Comments

Compare to g.f. of partitions in which no parts are multiples of 4:
g.f. of A001935 = exp( Integral (theta_3(x)^4-1)/(8x) dx ).

Examples

			G.f.: A(x) = 1 + x + 4*x^2 + 13*x^3 + 35*x^4 + 87*x^5 +...
log(A(x)) = x + 7*x^2/2 + 28*x^3/3 + 71*x^4/4 + 126*x^5/5 +...+ A008457(n)*x^n/n +...
		

Crossrefs

Programs

  • Mathematica
    nmax = 40; Abs[CoefficientList[Series[Product[1/(1 - x^k)^((-1)^k*k^2), {k, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Apr 10 2019 *)
    nmax = 40; CoefficientList[Series[Product[(1 + x^(2*k - 1))^((2*k - 1)^2)/(1 - x^(2*k))^(4*k^2), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Apr 10 2019 *)
  • PARI
    {a(n)=polcoeff(exp(sum(m=1,n, sumdiv(m,d,(-1)^(m-d)*d^3)*x^m/m)+x*O(x^n)),n)}
    
  • PARI
    {a(n)=local(theta3=1+sum(m=1,sqrtint(2*n+2),2*x^(m^2)+x*O(x^n)));polcoeff(exp(intformal((theta3^8-1)/(16*x))),n)}

Formula

G.f.: exp( Sum_{n>=1} A008457(n)*x^n/n ) where A008457(n) = Sum_{d|n} (-1)^(n-d)*d^3.
a(n) ~ exp(2*Pi*n^(3/4)/3 - Zeta(3)/Pi^2) / (4*n^(5/8)). - Vaclav Kotesovec, Apr 10 2019

A213598 Number of partitions of n in which no parts are multiples of 49.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, 101, 135, 176, 231, 297, 385, 490, 627, 792, 1002, 1255, 1575, 1958, 2436, 3010, 3718, 4565, 5604, 6842, 8349, 10143, 12310, 14883, 17977, 21637, 26015, 31185, 37338, 44583, 53174, 63261, 75175, 89134, 105558, 124754, 147273, 173524
Offset: 0

Views

Author

Michael Somos, Jun 14 2012

Keywords

Comments

For n<49 we have a(n)=A000041(n), for n>=49 a(n)!=A000041(n).
In Fricke page 401, he gives the expansion sigma(omega) = q^4 + q^6 + 2q^8 + 3q^10 + 5q^12 + 7q^14 + 11q^16 + 15q^18 + ... where q = exp( Pi i omega).

Examples

			G.f. = 1 + x + 2*x^2 + 3*x^3 + 5*x^4 + 7*x^5 + 11*x^6 + 15*x^7 + 22*x^8 + ...
G.f. = q^2 + q^3 + 2*q^4 + 3*q^5 + 5*q^6 + 7*q^7 + 11*q^8 + 15*q^9 + 22*q^10 + ...
		

References

  • R. Fricke, Die elliptischen Funktionen und ihre Anwendungen, Teubner, 1922, Vol. 2, see p. 401. Eq. (49)

Crossrefs

Cf. A000009 (m=2), A000726 (m=3), A001935 (m=4), A035959 (m=5), A219601 (m=6), A035985 (m=7), A261775 (m=8), A104502 (m=9), A261776 (m=10), A092885 (m=25), this sequence (m=49).

Programs

  • Mathematica
    a[ n_] := SeriesCoefficient[ Product[ 1 - x^k, {k, 49, n, 49}] / Product[ 1 - x^k, {k, n}], {x, 0, n}];
    a[ n_] := SeriesCoefficient[ QPochhammer[ x^49] / QPochhammer[ x], {x, 0, n}]; (* Michael Somos, May 13 2014 *)
  • PARI
    {a(n) = local(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^49 + A) / eta(x + A), n))};

Formula

Expansion of q^(-2) * eta(q^49) / eta(q) in powers of q.
Euler transform of period 49 sequence [ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, ...].
Given g.f. A(x) then B(x) = x^2 * A(x) satisfies 0 = f(B(x), B(x^2),
B(x^4)) where f(u, v, w) = u * v * w * (1 - 7*v^2) - (v - w) * (u - v) * (v^2 - u*w).
G.f. is a period 1 Fourier series which satisfies f(-1 / (49 t)) = 1 / (7 f(t)) where q = exp(2 Pi i t).
G.f.: Product_{k>0} (1 - x^(49*k)) / (1 - x^k).
a(n) ~ exp(4*Pi*sqrt(2*n)/7) / (2^(1/4) * 7^(3/2) * n^(3/4)). - Vaclav Kotesovec, Oct 14 2015
a(n) = (1/n)*Sum_{k=1..n} A287926(k)*a(n-k), a(0) = 1. - Seiichi Manyama, Jun 16 2017

A295342 The number of partitions of n in which at least one part is a multiple of 4.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 2, 3, 6, 8, 13, 18, 27, 37, 53, 71, 99, 131, 177, 232, 307, 397, 518, 663, 853, 1082, 1376, 1730, 2179, 2719, 3394, 4206, 5211, 6415, 7894, 9661, 11814, 14381, 17487, 21179, 25622, 30887, 37188, 44637, 53509, 63965, 76368, 90946, 108169, 128361
Offset: 0

Views

Author

R. J. Mathar, Nov 20 2017

Keywords

Crossrefs

Cf. A047967 (at least one multiple of 2), A295341 (at least one multiple of 3).

Formula

a(n) = A000041(n) - A001935(n).
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