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 1-9 of 9 results.

A092269 Spt function: total number of smallest parts (counted with multiplicity) in all partitions of n.

Original entry on oeis.org

1, 3, 5, 10, 14, 26, 35, 57, 80, 119, 161, 238, 315, 440, 589, 801, 1048, 1407, 1820, 2399, 3087, 3998, 5092, 6545, 8263, 10486, 13165, 16562, 20630, 25773, 31897, 39546, 48692, 59960, 73423, 89937, 109553, 133439, 161840, 196168, 236843, 285816, 343667, 412950, 494702, 592063, 706671
Offset: 1

Views

Author

Vladeta Jovovic, Feb 16 2004

Keywords

Comments

Row sums of triangle A220504. - Omar E. Pol, Jan 19 2013

Examples

			Partitions of 4 are [1,1,1,1], [1,1,2], [2,2], [1,3], [4]. 1 appears 4 times in the first, 1 twice in the second, 2 twice in the third, etc.; thus a(4)=4+2+2+1+1=10.
		

Crossrefs

For higher-order spt functions see A221140-A221144.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, n,
          `if`(irem(n, i, 'r')=0, r, 0)+add(b(n-i*j, i-1), j=0..n/i))
        end:
    a:= n-> b(n, n):
    seq(a(n), n=1..60);  # Alois P. Heinz, Jan 16 2013
  • Mathematica
    terms = 47; gf = Sum[x^n/(1 - x^n)*Product[1/(1 - x^k), {k, n, terms}], {n, 1, terms}]; CoefficientList[ Series[gf, {x, 0, terms}], x] // Rest (* Jean-François Alcover, Jan 17 2013 *)
    b[n_, i_] := b[n, i] = If[n==0 || i==1, n, {q, r} = QuotientRemainder[n, i]; If[r==0, q, 0] + Sum[b[n-i*j, i-1], {j, 0, n/i}]]; a[n_] := b[n, n]; Table[a[n], {n, 1, 60}] (* Jean-François Alcover, Nov 23 2015, after Alois P. Heinz *)
  • PARI
    N = 66;  x = 'x + O('x^N);
    gf = sum(n=1,N, x^n/(1-x^n) * prod(k=n,N, 1/(1-x^k) )  );
    v = Vec(gf)
    /* Joerg Arndt, Jan 12 2013 */

Formula

G.f.: Sum_{n>=1} x^n/(1-x^n) * Product_{k>=n} 1/(1-x^k).
a(n) = A000070(n-1) + A195820(n). - Omar E. Pol, Oct 19 2011
a(n) = n*p(n) - N_2(n)/2 = n*A000041(n) - A220908(n)/2 = A066186(n) - A220907(n) = (A220909(n) - A220908(n))/2 = A211982(n)/2 (from Andrews's paper and Garvan's paper). - Omar E. Pol, Jan 03 2013
a(n) = A000041(n) + A000070(n-2) + A220479(n), n >= 2. - Omar E. Pol, Feb 16 2013
Asymptotics (Bringmann-Mahlburg, 2009): a(n) ~ exp(Pi*sqrt(2*n/3)) / (Pi*sqrt(8*n)) ~ sqrt(6*n)*A000041(n)/Pi. - Vaclav Kotesovec, Jul 30 2017

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A092268 Total number of smallest parts in all partitions of n into odd parts.

Original entry on oeis.org

1, 2, 4, 5, 8, 12, 15, 20, 29, 36, 46, 61, 74, 95, 122, 145, 180, 224, 268, 328, 399, 474, 567, 682, 807, 955, 1136, 1330, 1564, 1842, 2140, 2499, 2914, 3375, 3917, 4533, 5220, 6014, 6929, 7942, 9102, 10430, 11898, 13582, 15489, 17600, 19999, 22706, 25719
Offset: 1

Views

Author

Vladeta Jovovic, Feb 16 2004

Keywords

Examples

			Partitions of 6 into odd parts are: [1,1,1,1,1,1], [1,1,1,3], [3,3], [1,5]; thus a(6)=6+3+2+1=12.
		

Crossrefs

Programs

  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[(x^(2*n - 1)/(1 - x^(2*n - 1))) / Product[(1 - x^(2*k - 1)), {k, n, nmax}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)

Formula

G.f.: Sum((x^(2*n-1)/(1-x^(2*n-1)))/Product((1-x^(2*k-1)), k=n..infinity), n=1..infinity).
a(n) ~ 3^(1/4) * exp(Pi*sqrt(n/3)) / (2*Pi*n^(1/4)). - Vaclav Kotesovec, Jul 07 2019

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A092311 Total number of largest parts in all partitions of n into odd parts.

Original entry on oeis.org

1, 2, 4, 5, 7, 10, 12, 14, 19, 23, 26, 33, 38, 44, 56, 63, 71, 88, 99, 114, 138, 155, 176, 208, 237, 269, 314, 357, 402, 468, 529, 594, 686, 772, 873, 999, 1119, 1260, 1431, 1608, 1804, 2039, 2284, 2554, 2884, 3219, 3590, 4032, 4493, 5011, 5603, 6231, 6928
Offset: 1

Views

Author

Vladeta Jovovic, Feb 16 2004

Keywords

Examples

			Partitions of 6 into odd parts are: [1,1,1,1,1,1], [1,1,1,3], [3,3], [1,5]; thus a(6)=6+1+2+1=10.
		

Crossrefs

Programs

  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[(x^(2*n - 1)/(1 - x^(2*n - 1))) / Product[(1 - x^(2*k - 1)), {k, 1, n}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)
    lpp[k_]:=Module[{c=Max[k]},Count[k,c]]; Table[Total[lpp/@Select[IntegerPartitions[ n],AllTrue[ #,OddQ]&]],{n, 60}] (* Harvey P. Dale, Apr 24 2023 *)

Formula

G.f.: Sum((x^(2*n-1)/(1-x^(2*n-1)))/Product((1-x^(2*k-1)), k=1..n), n=1..infinity).
a(n) ~ exp(Pi*sqrt(n/3)) / (4 * 3^(1/4) * n^(3/4)). - Vaclav Kotesovec, Jul 07 2019

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A092309 Sum of smallest parts (counted with multiplicity) of all partitions of n.

Original entry on oeis.org

1, 4, 7, 15, 19, 39, 46, 80, 106, 160, 201, 318, 390, 554, 729, 998, 1262, 1727, 2168, 2894, 3670, 4749, 5963, 7737, 9635, 12232, 15257, 19206, 23727, 29723, 36509, 45296, 55512, 68292, 83298, 102079, 123805, 150697, 182254, 220790, 265766
Offset: 1

Views

Author

Vladeta Jovovic, Feb 16 2004

Keywords

Examples

			Partitions of 4 are: [1,1,1,1], [1,1,2], [2,2], [1,3], [4]; thus a(4)=4*1+2*1+2*2+1*1+1*4=15.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(irem(n, i)=0, n, 0)
           +`if`(i>1, add(b(n-i*j, i-1), j=0..(n-1)/i), 0)
        end:
    a:= n-> b(n$2):
    seq(a(n), n=1..50);  # Alois P. Heinz, Feb 04 2016
  • Mathematica
    ss[n_]:=Module[{m=Min[n]},Select[n,#==m&]]; Table[Total[Flatten[ss/@ IntegerPartitions[n]]],{n,50}] (* Harvey P. Dale, Dec 16 2013 *)
    b[n_, i_] := b[n, i] = If[Mod[n, i] == 0, n, 0] + If[i > 1, Sum[b[n - i*j, i - 1], {j, 0, (n - 1)/i}], 0]; a[n_] := b[n, n]; Table[a[n], {n, 1, 50}] (* Jean-François Alcover, Aug 29 2016, after Alois P. Heinz *)

Formula

G.f.: Sum(n*x^n/(1-x^n)*Product(1/(1-x^k), k = n .. infinity), n = 1 .. infinity).
a(n) ~ sqrt(2) * exp(Pi*sqrt(2*n/3)) / (4*Pi*sqrt(n)). - Vaclav Kotesovec, Jul 06 2019

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A092321 Sum of largest parts (counted with multiplicity) of all partitions of n.

Original entry on oeis.org

0, 1, 4, 8, 17, 26, 49, 69, 115, 164, 249, 343, 513, 686, 974, 1314, 1806, 2382, 3232, 4208, 5597, 7244, 9456, 12118, 15687, 19899, 25422, 32079, 40589, 50796, 63805, 79303, 98817, 122179, 151145, 185820, 228598, 279476, 341807, 416051, 506205, 613244, 742720
Offset: 0

Views

Author

Vladeta Jovovic, Feb 16 2004

Keywords

Examples

			Partitions of 4 are [1,1,1,1], [1,1,2], [2,2], [1,3], [4]; thus a(4) = 4*1 + 1*2 + 2*2 + 1*3 + 1*4 = 17.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, t) option remember; `if`(n=0, [1, 0],
          `if`(i<1, [0$2], b(n, i-1, t) +add((l->`if`(t, l,
           l+[0, l[1]*i*j]))(b(n-i*j, i-1, true)), j=1..n/i)))
        end:
    a:= n-> b(n$2, false)[2]:
    seq(a(n), n=0..50);  # Alois P. Heinz, Jan 29 2014
  • Mathematica
    f[n_] := Block[{c = 2n, k = 2, p = IntegerPartitions[n]}, m = Max @@@ p; l = Length[p]; While[k < l, c = c + m[[k]]*Count[p[[k]], m[[k]]]; k++ ]; If[n == 1, 1, c]]; Table[ f[n], {n, 41}] (* Robert G. Wilson v, Feb 18 2004, updated by Jean-François Alcover, Jan 29 2014 *)
    nmax = 50; CoefficientList[Series[Sum[n*x^n/(1-x^n) * Product[1/(1 - x^k), {k, 1, n}], {n, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 06 2019 *)
    Join[{0},Table[Total[Flatten[First[Split[#]]&/@IntegerPartitions[n]]],{n,50}]] (* Harvey P. Dale, Oct 29 2019 *)

Formula

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

Extensions

More terms from Robert G. Wilson v, Feb 18 2004

A092314 Sum of smallest parts of all partitions of n into odd parts.

Original entry on oeis.org

1, 1, 4, 2, 7, 6, 11, 8, 18, 16, 24, 23, 34, 36, 51, 48, 66, 74, 90, 98, 126, 137, 164, 182, 220, 247, 294, 324, 380, 434, 496, 556, 650, 728, 835, 938, 1068, 1204, 1372, 1531, 1736, 1956, 2198, 2462, 2784, 3104, 3482, 3890, 4358, 4864, 5441, 6048, 6748, 7516
Offset: 1

Views

Author

Vladeta Jovovic, Feb 15 2004

Keywords

Comments

a(n) = Sum_{k>=1} k*A116856(n,k). - Emeric Deutsch, Feb 24 2006

Examples

			a(5)=7 because the partitions of 5 into odd parts are [5],[3,1,1] and [1,1,1,1,1] and the smallest parts add up to 5+1+1=7.
		

Crossrefs

Programs

  • Maple
    g:=sum((2*n-1)*x^(2*n-1)/Product(1-x^(2*k-1),k=n..30),n=1..30): gser:=series(g,x=0,57): seq(coeff(gser,x^n),n=1..54); # Emeric Deutsch, Feb 24 2006
  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[(2*n - 1)*x^(2*n - 1) / Product[(1 - x^(2*k - 1)), {k, n, nmax}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)

Formula

G.f.: Sum((2*n-1)*x^(2*n-1)/Product(1-x^(2*k-1), k = n .. infinity), n = 1 .. infinity).
a(n) ~ exp(Pi*sqrt(n/3)) / (4 * 3^(1/4) * n^(3/4)). - Vaclav Kotesovec, Jul 07 2019

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A092322 Sum of largest parts of all partitions of n into odd parts.

Original entry on oeis.org

1, 1, 4, 4, 9, 12, 19, 24, 36, 48, 64, 83, 108, 140, 179, 224, 280, 352, 432, 532, 652, 795, 960, 1160, 1392, 1669, 1992, 2368, 2804, 3320, 3908, 4592, 5388, 6300, 7349, 8560, 9940, 11524, 13340, 15401, 17752, 20436, 23472, 26920, 30840, 35256, 40252, 45900
Offset: 1

Views

Author

Vladeta Jovovic, Feb 15 2004

Keywords

Comments

a(n) = Sum_{k>=1} k*A116799(n,k). - Emeric Deutsch, Feb 24 2006

Examples

			a(5)=9 because the partitions of 5 into odd parts are [5],[3,1,1] and [1,1,1,1,1] and the largest parts add up to 5+3+1=9.
		

Crossrefs

Programs

  • Maple
    g:=sum((2*n-1)*x^(2*n-1)/Product(1-x^(2*k-1),k=1..n),n=1..30): gser:=series(g,x=0,50): seq(coeff(gser,x^n),n=1..48); # Emeric Deutsch, Feb 24 2006
  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[(2*n - 1)*x^(2*n - 1) / Product[(1 - x^(2*k - 1)), {k, 1, n}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)

Formula

G.f.: Sum_{n>=1} (2*n-1)*x^(2*n-1)/Product_{k=1..n} (1-x^(2*k-1)).

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A092310 Sum of largest parts (counted with multiplicity) of all partitions of n into odd parts.

Original entry on oeis.org

1, 2, 6, 7, 13, 20, 28, 34, 53, 71, 88, 117, 148, 188, 250, 301, 365, 472, 565, 688, 860, 1027, 1224, 1486, 1771, 2107, 2524, 2983, 3496, 4158, 4867, 5666, 6676, 7762, 9021, 10525, 12145, 14034, 16249, 18696, 21478, 24721, 28308, 32364, 37110, 42289
Offset: 1

Views

Author

Vladeta Jovovic, Feb 16 2004

Keywords

Examples

			Partitions of 6 into odd parts are: [1,1,1,1,1,1], [1,1,1,3], [3,3], [1,5]; thus a(6)=6*1+1*3+2*3+1*5=20.
		

Crossrefs

Programs

  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[(2*n - 1)*x^(2*n - 1)/(1 - x^(2*n - 1)) / Product[(1 - x^(2*k - 1)), {k, 1, n}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)

Formula

G.f.: Sum((2*n-1)*x^(2*n-1)/(1-x^(2*n-1))/Product(1-x^(2*k-1), k = 1 .. n), n = 1 .. infinity).

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A090794 Number of partitions of n such that the number of different parts is odd.

Original entry on oeis.org

1, 2, 2, 3, 2, 5, 4, 9, 13, 19, 27, 43, 54, 71, 102, 124, 161, 200, 257, 319, 400, 484, 618, 761, 956, 1164, 1450, 1806, 2226, 2741, 3367, 4137, 5020, 6163, 7485, 9042, 10903, 13172, 15721, 18956, 22542, 26925, 31935, 37962, 44861, 53183, 62651
Offset: 1

Views

Author

Vladeta Jovovic, Feb 12 2004

Keywords

Examples

			n=6 has A000041(6)=11 partitions: 6, 5+1, 4+2, 4+1+1, 3+3, 3+2+1, 3+1+1+1, 2+2+2, 2+2+1+1, 2+1+1+1+1 and 1+1+1+1+1+1 with partition sets: {6}, {1,5}, {2,4}, {1,4}, {3}, {1,2,3}, {1,3}, {2}, {1,2}, {1,2} and {1}, five of them have an odd number of elements, therefore a(6)=5.
		

Crossrefs

Programs

  • Haskell
    import Data.List (group)
    a090794 = length . filter odd . map (length . group) . ps 1 where
       ps x 0 = [[]]
       ps x y = [t:ts | t <- [x..y], ts <- ps t (y - t)]
    -- Reinhard Zumkeller, Dec 19 2013

Formula

a(n) = b(n, 1, 0, 0) with b(n, i, j, f) = if iReinhard Zumkeller, Feb 19 2004
G.f.: F(x)*G(x)/2, where F(x) = 1-Product(1-2*x^i, i=1..infinity) and G(x) = 1/Product(1-x^i, i=1..infinity).
a(n) = (A000041(n)-A104575(n))/2.
G.f. A(x) equals the off-diagonal entries in the 2 X 2 matrix Product_{n >= 1} [1, x^n/(1 - x^n); x^n/(1 - x^n), 1] = [B(x), A(x); A(x), B(x)], where B(x) is the g.f. of A092306. - Peter Bala, Feb 10 2021

Extensions

More terms from Reinhard Zumkeller, Feb 17 2004
Definition simplified and shortened by Jonathan Sondow, Oct 13 2013
Showing 1-9 of 9 results.