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.

Showing 1-10 of 12 results. Next

A045831 Number of 4-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 1, 3, 3, 3, 4, 4, 2, 2, 7, 3, 5, 6, 2, 4, 7, 3, 4, 7, 5, 8, 5, 4, 4, 8, 5, 6, 7, 2, 9, 11, 3, 8, 9, 4, 6, 5, 7, 5, 14, 7, 4, 10, 5, 10, 11, 3, 9, 10, 5, 8, 10, 4, 6, 15, 8, 9, 10, 6, 8, 15, 6, 10, 6, 5, 15, 9, 6, 8, 14, 8, 6, 13, 5, 16, 18, 7, 8, 7, 9, 6, 15, 6, 12, 17, 5, 8, 15, 7, 12
Offset: 0

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Author

Keywords

Comments

Ramanujan theta functions: f(q) (see A121373), phi(q) (A000122), psi(q) (A010054), chi(q) (A000700).
Conjecturally Sum_n a(n)q^(8n+5) equals theta series of sodalite. - Fred Lunnon, Mar 05 2015
Dickson writes that Liouville proved several related theorems about sums of triangular numbers. - Michael Somos, Feb 10 2020

Examples

			G.f. = 1 + x + 2*x^2 + 3*x^3 + x^4 + 3*x^5 + 3*x^6 + 3*x^7 + 4*x^8 + 4*x^9 + ...
G.f. = q^5 + q^13 + 2*q^21 + 3*q^29 + q^37 + 3*q^45 + 3*q^53 + 3*q^61 + 4*q^69 + ... ,
apparently the theta series of the sodalite net, aka edge-skeleton of space honeycomb by truncated octahedra. - _Fred Lunnon_, Mar 05 2015
		

References

  • L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. II, p. 23.

Crossrefs

A004024/4, column t=4 of A175595.
Cf. A286953.

Programs

  • Mathematica
    QP = QPochhammer; s = QP[q^4]^4/QP[q] + O[q]^100; CoefficientList[s, q] (* Jean-François Alcover, Jul 26 2011, updated Nov 29 2015 *)
  • PARI
    {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^4 + A)^4 / eta(x + A), n))}; /* Michael Somos, Mar 24 2003 */

Formula

eta(32*z)^4/eta(8*z) = Sum_{x, y, z} q^(x^2+2*y^2+2*z^2), x, y, z >= 1 and odd.
From Michael Somos, Mar 24 2003: (Start)
Euler transform of period 4 sequence [1, 1, 1, -3, ...].
Expansion of q^(-5/8) * eta(q^4)^4/eta(q) in powers of q.
(End)
Number of solutions to n=t1+2*t2+2*t3 where t1, t2, t3 are triangular numbers. - Michael Somos, Jan 02 2006
G.f.: Product_{k>0} (1-q^(4*k))^4/(1-q^k).
Expansion of psi(q) * psi(q^2)^2 in powers of q where psi() is a Ramanujan theta function. - Michael Somos, Sep 02 2008

Extensions

More terms from James Sellers, Feb 11 2000

A053723 Number of 5-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 2, 6, 5, 7, 5, 12, 6, 12, 6, 10, 11, 16, 7, 20, 15, 12, 12, 22, 10, 25, 12, 20, 18, 30, 10, 32, 21, 24, 16, 30, 21, 36, 20, 24, 25, 42, 12, 42, 36, 35, 22, 46, 22, 43, 25, 32, 36, 52, 20, 60, 30, 40, 30, 60, 30, 62, 32, 42, 43, 60, 24, 66, 48, 44, 30, 72, 35, 72
Offset: 0

Views

Author

James Sellers, Feb 11 2000

Keywords

Comments

Number 11 of the 74 eta-quotients listed in Table I of Martin (1996).

Examples

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

References

  • Srinivasa Ramanujan, The Lost Notebook and Other Unpublished Papers, Narosa Publishing House, New Delhi, 1988; see p. 54 (1.52).

Crossrefs

Programs

  • Mathematica
    a[n_]:=Total[KroneckerSymbol[#, 5]*n/# & /@ Divisors[n]]; Table[a[n], {n, 1, 73}] (* Jean-François Alcover, Jul 26 2011, after PARI prog. *)
    a[ n_] := SeriesCoefficient[ QPochhammer[ x^5]^5 / QPochhammer[ x], {x, 0, n}]; (* Michael Somos, Jul 13 2012 *)
    a[ n_] := With[{m = n + 1}, If[ m < 1, 0, DivisorSum[ m, m/# KroneckerSymbol[ 5, #] &]]]; (* Michael Somos, Jul 13 2012 *)
  • PARI
    {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^5 + A)^5 / eta(x + A), n))};
    
  • PARI
    {a(n) = if( n<0, 0, n++; sumdiv( n, d, kronecker( d, 5) * n/d))};
    
  • PARI
    {a(n) = if( n<0, 0, n++; direuler( p=2, n, 1 / ((1 - p*X) * (1 - kronecker( p, 5) * X)))[n])};

Formula

Given g.f. A(x), then B(q) = q * A(q) satisfies 0 = f(B(q), B(q^2), B(q^4)) where f(u, v, w) = v^3 + 2 * u*v*w + 4 * u*w^2 - u^2*w. - Michael Somos, May 02 2005
G.f.: (1/x) * (Sum_{k>0} Kronecker(k, 5) * x^k / (1 - x^k)^2). - Michael Somos, Sep 02 2005
G.f.: Product_{k>0} (1 - x^(5*k))^5 / (1 - x^k) = 1/x * (Sum_{k>0} k * x^k * (1 - x^k) * (1 - x^(2*k)) / (1 - x^(5*k))). - Michael Somos, Jun 17 2005
G.f.: (1/x) * Sum_{a, b, c, d, e in Z^5} x^((a^2 + b^2 + c^2 + d^2 + e^2) / 10) where a + b + c + d + e = 0, (a, b, c, d, e) == (0, 1, 2, 3, 4) (mod 5). - [Dyson 1972] Michael Somos, Aug 08 2007
Euler transform of period 5 sequence [ 1, 1, 1, 1, -4, ...].
Expansion of q^(-1) * eta(q^5)^5 / eta(q) in powers of q.
a(n) = b(n + 1) where b() is multiplicative with b(5^e) = 5^e, b(p^e) = (p^(e+1) - 1) / (p - 1) if p == 1, 4 (mod 5), b(p^e) = (p^(e+1) + (-1)^e) / (p + 1) if p == 2, 3 (mod 5).
Convolution inverse of A109063. a(n) = (-1)^n * A138512(n+1).
Convolution of A227216 and A229802. - Michael Somos, Jun 10 2014
G.f. is a period 1 Fourier series which satisfies f(-1 / (5 t)) = (1/5)^(1/2) (t/i)^2 g(t) where q = exp(2 Pi i t) and g() is the g.f. for A109064. - Michael Somos, May 17 2015
Sum_{k=1..n} a(k) ~ c * n^2 / 2, where c = A328717. - Amiram Eldar, Nov 23 2023

A053724 Number of 7-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 8, 15, 16, 21, 21, 28, 24, 44, 36, 49, 45, 63, 49, 74, 64, 85, 72, 105, 82, 133, 112, 120, 120, 165, 122, 180, 147, 186, 176, 225, 168, 255, 210, 245, 224, 324, 219, 338, 276, 341, 294, 385, 288, 441, 352, 410, 366, 518, 360, 506, 435, 504
Offset: 0

Views

Author

James Sellers, Feb 11 2000

Keywords

Examples

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

References

  • A. Balog, H. Darmon, K. Ono, Congruence for Fourier coefficients of half-integral weight modular forms and special values of L-functions, pp. 105-128 of Analytic number theory, Vol. 1, Birkhauser, Boston, 1996, see page 107.
  • B. Berndt, Commentary on Ramanujan's Papers, pp. 357-426 of Collected Papers of Srinivasa Ramanujan, Ed. G. H. Hardy et al., AMS Chelsea 2000. See page 372 (4).

Crossrefs

Cf. A053723, column t=7 of A175595.

Programs

  • Mathematica
    a[ n_] := SeriesCoefficient[ QPochhammer[ x^7]^7 / QPochhammer[ x], {x, 0, n}]; (* Michael Somos, Feb 22 2015 *)
  • PARI
    {a(n) = local(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^7 + A)^7 / eta(x + A), n))}; /* Michael Somos, Apr 16 2005 */

Formula

Expansion of q^(-2) * eta(q^7)^7 / eta(q) in powers of q.
Euler transform of period 7 sequence [ 1, 1, 1, 1, 1, 1, -6, ...].
a(7*n + 5) == 0 (mod 7).
G.f.: Product_{k>0} (1 - q^(7*k))^7 / (1 - q^k).

A286950 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} (1 - x^j)/(1 - x^(k*j))^k.

Original entry on oeis.org

1, 1, -1, 1, 0, -1, 1, -1, 0, 0, 1, -1, 1, 0, 0, 1, -1, -1, -2, 0, 1, 1, -1, -1, 3, 3, 0, 0, 1, -1, -1, 0, -3, -4, 0, 1, 1, -1, -1, 0, 4, -2, 5, 0, 0, 1, -1, -1, 0, 0, -3, 9, -7, 0, 0, 1, -1, -1, 0, 0, 6, -4, -8, 10, 0, 0, 1, -1, -1, 0, 0, 1, -5, 1, -6, -13, 0, 0, 1
Offset: 0

Views

Author

Seiichi Manyama, May 17 2017

Keywords

Examples

			Square array begins:
   1, 1,  1,  1,  1, ...
  -1, 0, -1, -1, -1, ...
  -1, 0,  1, -1, -1, ...
   0, 0, -2,  3,  0, ...
   0, 0,  3, -3,  4, ...
		

Crossrefs

Columns k=0-4 give: A010815, A000007, A106507, A286952, A286953.
Diagonal gives A286956.
Cf. A175595.

Formula

G.f. of column k: Product_{j>=1} (1 - x^j)/(1 - x^(k*j))^k.

A182803 Number of 8-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 14, 22, 26, 32, 37, 45, 47, 56, 75, 77, 89, 102, 111, 124, 142, 147, 167, 182, 196, 210, 242, 249, 288, 322, 299, 349, 382, 393, 423, 467, 453, 499, 570, 563, 602, 669, 649, 716, 772, 754, 843, 907, 884
Offset: 0

Views

Author

Alois P. Heinz, Dec 03 2010

Keywords

Crossrefs

8th column of A175595.

Programs

  • Maple
    with(numtheory): A:= proc(n, t) option remember; local d, j; `if`(n=0, 1, add(add(`if`(t=0 or irem(d, t)=0, d-d*t, d), d=divisors(j)) *A(n-j, t), j=1..n)/n) end: seq(A(n,8), n=0..50);
  • Mathematica
    A[n_, t_] := A[n, t] = If[n == 0, 1, Sum[Sum[If[t == 0 || Mod[d, t] == 0, d - d*t, d], {d, Divisors[j]}]*A[n - j, t], {j, 1, n}]/n];
    Table[A[n, 8], {n, 0, 50}] (* Jean-François Alcover, May 21 2018, translated form Maple *)

Formula

G.f.: Product_{i>=1} (1-x^(8*i))^8/(1-x^i).
Euler transform of period 8 sequence [1,1,1,1,1,1,1,-7, .. ].

A182804 Number of 9-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 21, 33, 38, 50, 56, 72, 77, 96, 99, 142, 139, 177, 180, 228, 229, 288, 284, 357, 343, 430, 410, 519, 491, 615, 588, 745, 714, 832, 811, 1007, 939, 1152, 1077, 1310, 1215, 1456, 1426, 1686, 1580, 1887, 1778, 2137
Offset: 0

Views

Author

Alois P. Heinz, Dec 03 2010

Keywords

Crossrefs

9th column of A175595.

Programs

  • Maple
    with(numtheory): A:= proc(n, t) option remember; local d, j; `if`(n=0, 1, add(add(`if`(t=0 or irem(d, t)=0, d-d*t, d), d=divisors(j)) *A(n-j, t), j=1..n)/n) end: seq(A(n,9), n=0..50);
  • Mathematica
    A[n_, t_] := A[n, t] = If[n == 0, 1, Sum[Sum[If[t == 0 || Mod[d, t] == 0, d - d*t, d], {d, Divisors[j]}]*A[n - j, t], {j, 1, n}]/n] ;
    Table[A[n, 9], {n, 0, 50}] (* Jean-François Alcover, May 21 2018, translated from Maple *)

Formula

G.f.: Product_{i>=1} (1-x^(9*i))^9/(1-x^i).
Euler transform of period 9 sequence [1,1,1,1,1,1,1,1,-8, .. ].

A182805 Number of 10-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 32, 46, 57, 71, 85, 106, 121, 147, 165, 190, 242, 267, 302, 350, 400, 443, 511, 565, 638, 715, 774, 852, 964, 1038, 1135, 1253, 1372, 1482, 1650, 1785, 1878, 2098, 2234, 2411, 2625, 2819, 2963, 3249, 3393, 3600, 4004, 4181
Offset: 0

Views

Author

Alois P. Heinz, Dec 03 2010

Keywords

Crossrefs

Programs

  • Maple
    with(numtheory): A:= proc(n, t) option remember; local d, j; `if`(n=0, 1, add(add(`if`(t=0 or irem(d, t)=0, d-d*t, d), d=divisors(j)) *A(n-j, t), j=1..n)/n) end: seq(A(n,10), n=0..50);
  • Mathematica
    A[n_, t_] := A[n, t] = Module[{d, j}, If[n == 0, 1, Sum[Sum[If[t == 0 || Mod[d, t] == 0, d - d t, d], {d, Divisors[j]}] A[n - j, t], {j, 1, n}]/n]];
    Table[A[n, 10], {n, 0, 50}] (* Jean-François Alcover, Dec 06 2020, after Alois P. Heinz *)

Formula

G.f.: Product_{i>=1} (1-x^(10*i))^10/(1-x^i).
Euler transform of period 10 sequence [1,1,1,1,1,1,1,1,1,-9, .. ].

A363675 Numbers k such that the least common multiple of the degrees of the irreducible characters of S_k equals |S_k| = k!.

Original entry on oeis.org

0, 1, 6, 10, 21, 36, 66, 105, 120, 136, 190, 210, 276, 325, 465, 496, 561, 630, 666, 741, 780, 990, 1081, 1176, 1225, 1540, 1596, 1830, 2080, 2145, 2346, 2556, 2926, 3081, 3160, 3240, 3486, 3570, 3916, 4005, 4186, 4560, 4656, 4950, 5050, 5356, 5460, 5886, 6105
Offset: 1

Views

Author

Diego Martin Duro, Jun 14 2023

Keywords

Comments

Intersection of the sequences of numbers k such that there exists a 2-core partition of k (A267137) and a 3-core partition of k (A000217).

Crossrefs

Formula

From Alois P. Heinz, Jun 16 2023: (Start)
{ k : A175595(k,2) > 0 and A175595(k,3) > 0 }.
{ k : A010054(k) > 0 and A033687(k) > 0 }. (End)

Extensions

More terms from Alois P. Heinz, Jun 16 2023

A053691 Number of 11-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 45, 66, 79, 102, 121, 154, 176, 220, 248, 297, 330, 430, 452, 552, 605, 720, 777, 935, 990, 1182, 1265, 1485, 1530, 1838, 1892, 2214, 2310, 2684, 2750, 3238, 3289, 3850, 3960, 4500, 4599, 5370, 5404, 6220, 6325, 7238
Offset: 0

Views

Author

James Sellers, Feb 14 2000

Keywords

Comments

Ramanujan theta functions: f(q) (see A121373), phi(q) (A000122), psi(q) (A010054), chi(q) (A000700).

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^5 + q^6 + 2*q^7 + 3*q^8 + 5*q^9 + 7*q^10 + 11*q^11 + 15*q^12 + ...
		

Crossrefs

Column t=11 of A175595.

Programs

  • Mathematica
    m = 50; CoefficientList[ Series[ Product[(1-q^(11*k))^11/(1-q^k), {k, 1, m}], {q, 0, m}], q] (* Jean-François Alcover, Jul 26 2011, after g.f. *)
    a[ n_] := SeriesCoefficient[ QPochhammer[ x^11]^11 / QPochhammer[ x], {x, 0, n}]; (* Michael Somos, Nov 06 2014 *)
  • PARI
    {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^11 + A)^11 / eta(x + A), n))}; /* Michael Somos, Nov 06 2014 */

Formula

Expansion of f(-x^11)^11 / f(-x) in powers of x where f() is a Ramanujan theta function.
Expansion of q^-5 * etq(q^11)^11 / eta(q) in powers of q. - Michael Somos, Nov 06 2014
Euler transform of period 11 sequence [ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -10, ...]. - Michael Somos, Nov 06 2014
G.f. Product_{k>0} (1 - x^(11*k))^11 / (1 - x^k).

A192061 Number of 12-core partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 65, 89, 111, 140, 171, 213, 253, 310, 363, 432, 498, 583, 705, 800, 924, 1060, 1216, 1379, 1578, 1772, 2013, 2259, 2554, 2847, 3147, 3507, 3897, 4305, 4756, 5225, 5748, 6297, 6909, 7546, 8250, 9000, 9724, 10626, 11512, 12478, 13482, 14616, 15714, 17007, 18215, 19602, 20930, 22470
Offset: 0

Views

Author

N. J. A. Sloane, Jun 21 2011

Keywords

Crossrefs

A column of A175595.

Programs

  • Maple
    M:=60;
    f:=proc(t) global M; local q,i,t1;
    t1:=1;
    for i from 1 to M+1 do
    t1:=series(t1*(1-q^(i*t))^t,q,M);
    t1:=series(t1/(1-q^i),q,M);
    od;
    t1;
    end;
    seriestolist(f(12));
  • Mathematica
    m = 60;
    f[0] = 1/(1 - x^k);
    f[t_] = (1 - x^(k t))^t/(1 - x^k);
    s[t_] := CoefficientList[Series[Product[f[t], {k, m-1}], {x, 0, m-1}], x];
    s[12] (* Jean-François Alcover, May 27 2020 *)
Showing 1-10 of 12 results. Next