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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A347543 Number of partitions of n into 7 or more parts.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 30, 45, 66, 95, 134, 186, 255, 345, 461, 611, 801, 1043, 1346, 1727, 2199, 2787, 3508, 4398, 5482, 6809, 8414, 10365, 12711, 15545, 18935, 23006, 27854, 33646, 40513, 48680, 58326, 69748, 83192, 99048, 117650, 139513, 165083, 195034, 229968, 270760
Offset: 7

Views

Author

Ilya Gutkovskiy, Sep 06 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 52; CoefficientList[Series[Sum[x^k/Product[(1 - x^j), {j, 1, k}], {k, 7, nmax}], {x, 0, nmax}], x] // Drop[#, 7] &

Formula

G.f.: Sum_{k>=7} x^k / Product_{j=1..k} (1 - x^j).

A347544 Number of partitions of n into 8 or more parts.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 30, 45, 67, 96, 137, 190, 263, 356, 480, 637, 842, 1098, 1427, 1835, 2351, 2986, 3780, 4749, 5949, 7405, 9190, 11344, 13966, 17111, 20913, 25454, 30908, 37393, 45141, 54315, 65222, 78090, 93317, 111220, 132323, 157050, 186088, 220015, 259716
Offset: 8

Views

Author

Ilya Gutkovskiy, Sep 06 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 52; CoefficientList[Series[Sum[x^k/Product[(1 - x^j), {j, 1, k}], {k, 8, nmax}], {x, 0, nmax}], x] // Drop[#, 8] &

Formula

G.f.: Sum_{k>=8} x^k / Product_{j=1..k} (1 - x^j).

A347545 Number of partitions of n into 9 or more parts.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 30, 45, 67, 97, 138, 193, 267, 364, 491, 656, 868, 1139, 1483, 1917, 2461, 3142, 3985, 5030, 6315, 7893, 9817, 12165, 15007, 18451, 22597, 27589, 33565, 40724, 49249, 59410, 71460, 85753, 102632, 122574, 146032, 173638, 206003, 243951, 288296, 340124
Offset: 9

Views

Author

Ilya Gutkovskiy, Sep 06 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 54; CoefficientList[Series[Sum[x^k/Product[(1 - x^j), {j, 1, k}], {k, 9, nmax}], {x, 0, nmax}], x] // Drop[#, 9] &

Formula

G.f.: Sum_{k>=9} x^k / Product_{j=1..k} (1 - x^j).

A347547 Number of partitions of n into 10 or more parts.

Original entry on oeis.org

1, 2, 4, 7, 12, 19, 30, 45, 67, 97, 139, 194, 270, 368, 499, 667, 887, 1165, 1524, 1973, 2544, 3253, 4143, 5239, 6602, 8268, 10320, 12813, 15859, 19537, 24000, 29359, 35820, 43541, 52795, 63803, 76929, 92476, 110926, 132694, 158414, 188649, 224231, 265916, 314793
Offset: 10

Views

Author

Ilya Gutkovskiy, Sep 06 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 54; CoefficientList[Series[Sum[x^k/Product[(1 - x^j), {j, 1, k}], {k, 10, nmax}], {x, 0, nmax}], x] // Drop[#, 10] &

Formula

G.f.: Sum_{k>=10} x^k / Product_{j=1..k} (1 - x^j).

A029894 Number of directed (or Gale-Ryser) graphical partitions: degree-vector pairs (in-degree, out-degree) for directed graphs (loops allowed) with n vertices; or possible ordered pair (row-sum, column-sum) vectors for a 0-1 matrix.

Original entry on oeis.org

1, 2, 7, 34, 221, 1736, 15584, 153228, 1611189, 17826202, 205282376, 2441437708, 29816628471, 372314544202, 4737438631001, 61264426341926, 803488037899349, 10668478221202710, 143203795004873285, 1940953294927992976, 26536578116407809962, 365653739580163294032
Offset: 0

Views

Author

torsten.sillke(AT)lhsystems.com

Keywords

References

  • R. A. Brualdi, H. J. Ryser, Combinatorial Matrix Theory, Cambridge Univ. Press, 1992.

Crossrefs

Main diagonal of A327913.

Programs

Formula

Calculated using Cor. 6.3.3, Th. 6.3.6, Cor. 6.2.5 of Brualdi-Ryser.
a(n) = F(n, n, 0, n) where F(b, c, t, w) = Sum_{i=0..b} Sum_{j=ceiling((t+i)/w)..min(t+i, c)} F(i, j, t+i-j, w-1) for w > 0, F(b, c, 0, 0) = 1 and F(b, c, t, 0) = 0 for t > 0. - Andrew Howroyd, Nov 01 2019

Extensions

"Loops allowed" added to the definition by Brendan McKay, Oct 20 2015
a(0)=1 prepended and terms a(12) and beyond from Andrew Howroyd, Oct 31 2019

A283826 Irregular triangle read by rows: T(n,k) = number of trees on n nodes with radius k, n>=1, 1 <= k <= floor(n/2).

Original entry on oeis.org

0, 1, 1, 1, 1, 1, 2, 1, 4, 1, 1, 7, 3, 1, 11, 10, 1, 1, 17, 25, 4, 1, 25, 61, 18, 1, 1, 36, 132, 61, 5, 1, 50, 277, 194, 28, 1, 1, 70, 554, 553, 117, 6, 1, 94, 1077, 1495, 451, 40, 1, 1, 127, 2034, 3823, 1552, 197, 7, 1, 168, 3770, 9427, 5020, 879, 54, 1, 1, 222, 6853, 22466, 15289, 3485, 305, 8, 1
Offset: 1

Views

Author

N. J. A. Sloane, Mar 19 2017

Keywords

Comments

The radius of a tree is the maximal distance of a node from the center.

Examples

			Triangle begins:
  0,
  1,
  1,
  1,  1,
  1,  2,
  1,  4,   1,
  1,  7,   3,
  1, 11,  10,   1,
  1, 17,  25,   4,
  1, 25,  61,  18,  1,
  1, 36, 132,  61,  5,
  1, 50, 277, 194, 28, 1,
  ...
		

Crossrefs

Cf. A283827.
See also A000676, A000677, A027416, A102911, A004250 (column 2?), A000055 (row sums).

Formula

T(n,k) = A034853(n,2k-1) + A034853(n,2k). - R. J. Mathar, Apr 03 2017

A007722 Number of graphical partitions of biconnected graphs with n nodes.

Original entry on oeis.org

1, 3, 9, 34, 125, 473, 1779, 6732, 25492, 96927, 369463, 1412700, 5415117, 20807502, 80120350, 309106496, 1194609429, 4624160156, 17925278497, 69578272204, 270401326899, 1052036082719, 4097343156323, 15973179953261, 62325892264031, 243392644741599
Offset: 3

Views

Author

Keywords

References

  • F. Ruskey, Alley CATs in search of good homes, Congress. Numerant., 102 (1994) 97-110.

Crossrefs

Extensions

a(15)-a(28) added by Kai Wang, Feb 15 2017

A029890 Number of odd graphical partitions.

Original entry on oeis.org

1, 2, 7, 20, 70, 234, 832, 2956, 10759, 39394, 145892, 543564, 2038831, 7684116, 29092055, 110550260, 421495147, 1611662256
Offset: 1

Views

Author

TORSTEN.SILLKE(AT)LHSYSTEMS.COM

Keywords

References

  • R. A. Brualdi, H. J. Ryser, Combinatorial Matrix Theory, Cambridge Univ. Press, 1992.

Crossrefs

Formula

Calculated using Cor. 6.3.3, Th. 6.3.6, Cor. 6.2.5 of Brualdi-Ryser.

A029891 Number of even graphical partitions.

Original entry on oeis.org

1, 3, 7, 23, 70, 242, 832, 2983, 10759, 39482, 145892, 543877, 2038831, 7685211, 29092055, 110554267, 421495147, 1611676767
Offset: 1

Views

Author

TORSTEN.SILLKE(AT)LHSYSTEMS.COM

Keywords

References

  • R. A. Brualdi, H. J. Ryser, Combinatorial Matrix Theory, Cambridge Univ. Press, 1992.

Crossrefs

Formula

Calculated using Cor. 6.3.3, Th. 6.3.6, Cor. 6.2.5 of Brualdi-Ryser.

A259873 Triangle read by rows: T(n,k) (n >= 3, 3 <= k <= n) = number of possible graphical partitions for simple graphs with n non-isolated nodes and k edges.

Original entry on oeis.org

1, 0, 2, 0, 1, 4, 0, 1, 4, 7, 0, 0, 4, 9, 11, 0, 0, 2, 11, 15, 17, 0, 0, 1, 11, 22, 25, 25, 0, 0, 1, 9, 26, 38, 37, 36, 0, 0, 0, 7, 29, 49, 58, 55, 50, 0, 0, 0, 5, 29, 63, 81, 87, 77, 70
Offset: 3

Views

Author

N. J. A. Sloane, Jul 09 2015

Keywords

Examples

			Triangle begins:
1,
0,2,
0,1,4,
0,1,4,7,
0,0,4,9,11,
0,0,2,11,15,17,
0,0,1,11,22,25,25,
0,0,1,9,26,38,37,36,
0,0,0,7,29,49,58,55,50,
0,0,0,5,29,63,81,87,77,70,
...
		

References

  • P. R. Stein, On the number of graphical partitions, pp. 671-684 of Proc. 9th S-E Conf. Combinatorics, Graph Theory, Computing, Congr. Numer. 21 (1978). Contains table for n <= 27.

Crossrefs

A004250 is a diagonal. Cf. A000088, A004251.
Previous Showing 21-30 of 38 results. Next