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 14 results. Next

A340793 Sequence whose partial sums give A000203.

Original entry on oeis.org

1, 2, 1, 3, -1, 6, -4, 7, -2, 5, -6, 16, -14, 10, 0, 7, -13, 21, -19, 22, -10, 4, -12, 36, -29, 11, -2, 16, -26, 42, -40, 31, -15, 6, -6, 43, -53, 22, -4, 34, -48, 54, -52, 40, -6, -6, -24, 76, -67, 36, -21, 26, -44, 66, -48, 48, -40, 10, -30, 108, -106, 34, 8
Offset: 1

Views

Author

Omar E. Pol, Jan 21 2021

Keywords

Comments

Essentially a duplicate of A053222.
Convolved with the nonzero terms of A000217 gives A175254, the volume of the stepped pyramid described in A245092.
Convolved with the nonzero terms of A046092 gives A244050, the volume of the stepped pyramid described in A244050.
Convolved with A000027 gives A024916.
Convolved with A000041 gives A138879.
Convolved with A000070 gives the nonzero terms of A066186.
Convolved with the nonzero terms of A002088 gives A086733.
Convolved with A014153 gives A182738.
Convolved with A024916 gives A000385.
Convolved with A036469 gives the nonzero terms of A277029.
Convolved with A091360 gives A276432.
Convolved with A143128 gives the nonzero terms of A000441.
For the correspondence between divisors and partitions see A336811.

Crossrefs

Programs

  • Maple
    a:= n-> (s-> s(n)-s(n-1))(numtheory[sigma]):
    seq(a(n), n=1..77);  # Alois P. Heinz, Jan 21 2021
  • Mathematica
    Join[{1}, Differences @ Table[DivisorSigma[1, n], {n, 1, 100}]] (* Amiram Eldar, Jan 21 2021 *)
  • PARI
    a(n) = if (n==1, 1, sigma(n)-sigma(n-1)); \\ Michel Marcus, Jan 22 2021

Formula

a(n) = A053222(n-1) for n>1. - Michel Marcus, Jan 22 2021

A091355 Triangle read by rows: T(n,k) = number of planar partitions of n with k rows.

Original entry on oeis.org

1, 2, 1, 3, 2, 1, 5, 5, 2, 1, 7, 9, 5, 2, 1, 11, 18, 11, 5, 2, 1, 15, 30, 22, 11, 5, 2, 1, 22, 53, 42, 24, 11, 5, 2, 1, 30, 85, 78, 46, 24, 11, 5, 2, 1, 42, 139, 138, 90, 48, 24, 11, 5, 2, 1, 56, 215, 239, 164, 94, 48, 24, 11, 5, 2, 1, 77, 336, 405, 298, 176, 96, 48, 24, 11, 5, 2, 1, 101, 504, 669, 520, 324, 180, 96, 48, 24, 11, 5, 2, 1
Offset: 1

Views

Author

Christian G. Bower, Jan 02 2004

Keywords

Comments

Row sums give A000219.
Columns 1-5 are respectively A000041, A091356, A091357, A091358, and A091359.
Columns converge to A091360.

Examples

			Triangle starts:
01:  1,
02:  2, 1,
03:  3, 2, 1,
04:  5, 5, 2, 1,
05:  7, 9, 5, 2, 1,
06:  11, 18, 11, 5, 2, 1,
07:  15, 30, 22, 11, 5, 2, 1,
08:  22, 53, 42, 24, 11, 5, 2, 1,
09:  30, 85, 78, 46, 24, 11, 5, 2, 1,
10:  42, 139, 138, 90, 48, 24, 11, 5, 2, 1,
11:  56, 215, 239, 164, 94, 48, 24, 11, 5, 2, 1,
12:  77, 336, 405, 298, 176, 96, 48, 24, 11, 5, 2, 1,
13:  101, 504, 669, 520, 324, 180, 96, 48, 24, 11, 5, 2, 1,
14:  135, 760, 1088, 899, 580, 336, 182, 96, 48, 24, 11, 5, 2, 1,
15:  176, 1115, 1741, 1512, 1020, 606, 340, 182, 96, 48, 24, 11, 5, 2, 1,
...
		

Programs

  • Maple
    with(numtheory):
    A:= proc(n, k) option remember; `if`(n=0, 1, add(add(
          min(d, k)*d, d=divisors(j))*A(n-j, k), j=1..n)/n)
        end:
    T:= (n, k)-> A(n, k)-`if`(k=0, 0, A(n, k-1)):
    seq(seq(T(n, k), k=1..n), n=1..15);  # Alois P. Heinz, Mar 15 2014
  • Mathematica
    (* load EulerTransform from 'seqtranslib.m' under OEIS-Transforms *) Table[EulerTransform[Table[Min[c, r], {r, 20}]] - EulerTransform[Table[Min[c-1, r], {r, 20}]], {c, 20}] // Transpose
    (* second program: *)
    A[n_, k_] := A[n, k] = If[n == 0, 1, Sum[Sum[Min[d, k]*d, {d, Divisors[j]}] *A[n-j, k], {j, 1, n}]/n]; T[n_, k_] := A[n, k] - If[k == 0, 0, A[n, k-1] ]; Table[Table[T[n, k], {k, 1, n}], {n, 1, 15}] // Flatten (* Jean-François Alcover, Jan 23 2016, after Alois P. Heinz *)

Formula

k-th column is EulerTransform[1, 2, 3, .., k, k, k, ..]-EulerTransform[1, 2, 3, .., k-1, k-1, k-1, ..]. - Wouter Meeussen, Aug 29 2004

Extensions

Definition corrected, Joerg Arndt, Jul 21 2014

A091356 Number of planar partitions of n with exactly 2 rows.

Original entry on oeis.org

1, 2, 5, 9, 18, 30, 53, 85, 139, 215, 336, 504, 760, 1115, 1635, 2351, 3375, 4770, 6725, 9368, 13006, 17885, 24510, 33319, 45139, 60743, 81457, 108610, 144334, 190844, 251542, 330082, 431825, 562710, 731154, 946644, 1222305, 1573155, 2019471
Offset: 2

Views

Author

Christian G. Bower, Jan 02 2004

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, k) option remember; `if`(n=0, 1, add(add(min(d, k)
         *d, d=numtheory[divisors](j))*b(n-j, k), j=1..n)/n)
        end:
    a:= n-> b(n, 2)-b(n, 1):
    seq(a(n), n=2..50);  # Alois P. Heinz, Oct 02 2018
  • Mathematica
    b[n_, k_] := b[n, k] = If[n == 0, 1, Sum[Sum[Min[d, k] d, {d, Divisors[j]}] b[n - j, k], {j, 1, n}]/n];
    a[n_] :=  b[n, 2] - b[n, 1];
    a /@ Range[2, 50] (* Jean-François Alcover, Oct 28 2020, after Alois P. Heinz *)

Formula

a(n) = A000990(n) - A000041(n).

A092288 Triangle read by rows: T(n,k) = count of parts k in all plane partitions of n.

Original entry on oeis.org

1, 4, 1, 11, 2, 1, 28, 7, 2, 1, 62, 15, 5, 2, 1, 137, 38, 13, 5, 2, 1, 278, 76, 28, 11, 5, 2, 1, 561, 164, 60, 26, 11, 5, 2, 1, 1080, 316, 124, 52, 24, 11, 5, 2, 1, 2051, 623, 244, 108, 50, 24, 11, 5, 2, 1, 3778, 1156, 469, 208, 100, 48, 24, 11, 5, 2, 1, 6885, 2160, 886, 404, 194, 98, 48, 24, 11, 5, 2, 1
Offset: 1

Views

Author

Wouter Meeussen, Feb 01 2004

Keywords

Comments

For large n the rows end in A091360 = partial sums of A000219 (count of plane partitions).

Examples

			Triangle begins:
    1;
    4,  1;
   11,  2,  1;
   28,  7,  2,  1;
   62, 15,  5,  2,  1;
  137, 38, 13,  5,  2,  1;
  ...
		

Crossrefs

Column k=1 gives A090539.
Row sums give A319648.
T(2n+1,n+1) gives A091360.

Programs

  • Mathematica
    Table[Length /@ Split[Sort[Flatten[planepartitions[k]]]], {k, 12}]
  • PARI
    A092288_row(n, c=vector(n), m, k)={for(i=1, #n=PlanePartitions(n), for(j=1,#m=n[i], for(i=1,#k=m[j], c[k[i]]++))); c} \\ See A091298 for PlanePartitions(). See below for more efficient code.
    M92288=[]; A092288(n,k,L=0)={n>1||return(if(L,[n,n==k],n==k)); if(#L&& #L<3, my(j=setsearch(M92288,[[n,k,L],[]],1)); j<=#M92288&& M92288[j][1]==[n,k,L]&& return(M92288[j][2])); my(c(p)=sum(i=1,#p,p[i]==k),S=[0,0],t); for(m=1,n,my(P=if(L,select(p->vecmin(L-Vecrev(p,#L))>=0, partitions(m,L[1],#L)), partitions(m))); if(mA092288(n-m,k,Vecrev(P[i])); S+=[t[1], t[1]*c(P[i])+t[2]], S+=[#P,vecsum(apply(c,P))])); if(L, #L<3&& M92288= setunion(M92288,[[[n,k,L],S]]);S,S[2])} \\ M. F. Hasler, Sep 26 2018

A302830 Expansion of (1/(1 - x))*Product_{k>=1} 1/(1 - k*x^k).

Original entry on oeis.org

1, 2, 5, 11, 25, 50, 106, 203, 401, 755, 1427, 2597, 4804, 8566, 15352, 27027, 47551, 82187, 142445, 243025, 414919, 700739, 1181236, 1972552, 3293898, 5450728, 9008081, 14791741, 24244399, 39494615, 64266141, 103979929, 167991853, 270190879, 433773933, 693518984
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 13 2018

Keywords

Comments

Partial sums of A006906.

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
           b(n, i-1)+add(b(n-i*j, i-1)*(i^j), j=1..n/i)))
        end:
    a:= proc(n) option remember; `if`(n<0, 0, a(n-1)+b(n$2)) end:
    seq(a(n), n=0..40);  # Alois P. Heinz, Apr 13 2018
  • Mathematica
    nmax = 35; CoefficientList[Series[1/(1 - x) Product[1/(1 - k x^k), {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 35; CoefficientList[Series[1/(1 - x) Exp[Sum[Sum[k^j x^(j k)/j, {k, 1, nmax}], {j, 1, nmax}]], {x, 0, nmax}], x]

Formula

G.f.: (1/(1 - x))*exp(Sum_{j>=1} Sum_{k>=1} k^j*x^(j*k)/j).
From Vaclav Kotesovec, Apr 14 2018: (Start)
a(n) ~ c * 3^(n/3), where
c = 319343.48587983201292657132469068725642363369445... if mod(n,3)=0
c = 319343.34569378454521307030620964478962032866022... if mod(n,3)=1
c = 319343.21458897980925594955657564398036486423380... if mod(n,3)=2
(End)

A091357 Number of planar partitions of n with exactly 3 rows.

Original entry on oeis.org

1, 2, 5, 11, 22, 42, 78, 138, 239, 405, 669, 1088, 1741, 2744, 4267, 6564, 9975, 15019, 22394, 33111, 48549, 70678, 102127, 146636, 209186, 296697, 418401, 586985, 819218, 1137962, 1573336, 2165888, 2968914, 4053563, 5512820, 7469989
Offset: 3

Views

Author

Christian G. Bower, Jan 02 2004

Keywords

Crossrefs

Column 3 of A091355.

Formula

a(n) = A000991(n)-A000990(n).

A276432 Sum of the traces of all plane partitions of n.

Original entry on oeis.org

1, 4, 10, 26, 56, 126, 252, 512, 980, 1866, 3427, 6258, 11121, 19618, 33975, 58328, 98732, 165804, 275246, 453544, 740338, 1200088, 1929897, 3083898, 4893775, 7720826, 12106814, 18883104, 29291740, 45215386, 69451631, 106197524, 161656759, 245050410, 369935066
Offset: 1

Views

Author

Emeric Deutsch, Sep 24 2016

Keywords

Comments

Convolution of A000203 and A000219. - Vaclav Kotesovec, Sep 25 2016
Convolution of A340793 and A091360. - Omar E. Pol, Feb 16 2021

Examples

			a(3) = 10 because the 6 (=A000219(3)) planar partitions of 3 are [3], [2,1], [2;1], [1,1,1], [1;1;1], [1,1;1] (; indicates a new row); the sum of their traces is 3+2+2+1+1+1 = 10.
		

References

  • G. E. Andrews, The Theory of Partitions, Addison-Wesley, 1976, pp. 179-201.

Crossrefs

Programs

  • Maple
    g:= (sum(j*x^j/(1-x^j),j = 1..100))/(product((1-x^k)^k,k = 1..100)): gser := series(g, x = 0,40): seq(coeff(gser, x, m), m = 1 .. 35);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<1, 0, add((p
          ->p+[0, j*p[1]])(b(n-i*j, i-1))*binomial(i+j-1, j), j=0..n/i)))
        end:
    a:= n-> b(n$2)[2]:
    seq(a(n), n=1..50);  # Alois P. Heinz, Sep 24 2018
  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[j*x^j/(1-x^j), {j, 1, nmax}]*Product[1/(1-x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Sep 25 2016 *)

Formula

G.f.: g(x) = Sum_{j>=1} (j*x^j/(1-x^j))/Product_{k>=1} (1-x^k)^k.
a(n) = Sum(k*A089353(n,k), k>=1).

A302832 Expansion of (1/(1 - x))*Product_{k>=1} (1 + x^k)^k.

Original entry on oeis.org

1, 2, 4, 9, 17, 33, 61, 110, 193, 335, 570, 955, 1582, 2586, 4185, 6706, 10646, 16757, 26178, 40587, 62503, 95637, 145445, 219929, 330766, 494898, 736858, 1092027, 1611185, 2367079, 3463490, 5048009, 7329935, 10605211, 15290942, 21973641, 31475620, 44946859, 63991639, 90842560
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 13 2018

Keywords

Comments

Partial sums of A026007.

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember;
          add((-1)^(n/d+1)*d^2, d=numtheory[divisors](n))
        end:
    g:= proc(n) option remember;
          `if`(n=0, 1, add(b(k)*g(n-k), k=1..n)/n)
        end:
    a:= proc(n) option remember; `if`(n<0, 0, a(n-1)+g(n)) end:
    seq(a(n), n=0..40);  # Alois P. Heinz, Apr 13 2018
  • Mathematica
    nmax = 39; CoefficientList[Series[1/(1 - x) Product[(1 + x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x]
    nmax = 39; CoefficientList[1/(1 - x) Series[Exp[Sum[(-1)^(k + 1) x^k/(k (1 - x^k)^2), {k, 1, nmax}]], {x, 0, nmax}], x]

Formula

G.f.: (1/(1 - x))*exp(Sum_{k>=1} (-1)^(k+1)*x^k/(k*(1 - x^k)^2)).
From Vaclav Kotesovec, Apr 13 2018: (Start)
a(n) ~ exp((3/2)^(4/3) * Zeta(3)^(1/3) * n^(2/3)) / (2^(5/12) * 3^(2/3) * sqrt(Pi) * Zeta(3)^(1/6) * n^(1/3)).
a(n) ~ (2*n/(3*Zeta(3)))^(1/3) * A026007(n).
a(n) ~ erfi((3/2)^(2/3) * Zeta(3)^(1/6) * n^(1/3)) / 2^(13/12).
(End)

A091358 Number of planar partitions of n with exactly 4 rows.

Original entry on oeis.org

1, 2, 5, 11, 24, 46, 90, 164, 298, 520, 899, 1512, 2521, 4116, 6659, 10609, 16753, 26126, 40419, 61889, 94067, 141736, 212123, 315087, 465162, 682188, 994857, 1442340, 2080332, 2984724, 4262018, 6056849, 8569913, 12072770, 16938556
Offset: 4

Views

Author

Christian G. Bower, Jan 02 2004

Keywords

Crossrefs

Column 4 of A091355. Cf. A000219, A091356-A091360.

Formula

a(n) = A002799(n)-A000991(n).

A091359 Number of planar partitions of n with exactly 5 rows.

Original entry on oeis.org

1, 2, 5, 11, 24, 48, 94, 176, 324, 580, 1020, 1757, 2985, 4990, 8237, 13428, 21651, 34540, 54583, 85473, 132730, 204484, 312695, 474814, 716217, 1073558, 1599568, 2369781, 3491812, 5118490, 7465789, 10837964, 15661666, 22533586, 32284480
Offset: 5

Views

Author

Christian G. Bower, Jan 02 2004

Keywords

Crossrefs

Column 5 of A091355. Cf. A000219, A091356-A091360.

Formula

a(n) = A001452(n)-A002799(n).
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